Bald cypress is considered a magic tree in China. While the tree is an “exotic” only in the country for a little over a hundred years, it has found favor with land use managers on a scale that’s difficult to believe unless you see it on the ground . . . work in progress . . . stay tuned
INTRODUCTION: First, let me say that golden kiwifruit are complicated. A robust deciduous vine from China, the plants are dioecious (there’s a male plant and a female plant). However, it can’t be just any male. It has to be the right male, one that provides pollen when the female flower is receptive. It’s all about timing. The vine has plenty of attributes. This is a super fruit, one packed with vitamins and minerals. It can live over a hundred years and trunks over 1′ wide are not unheard of. There’s an economic message here as well. In a well managed operation, yields of 40,000 to 50,000 lbs. per acre are feasible. With $2.99 per lb. clamshells the norm in the produce aisle, you do the math. The cost of building a trellis or pergola system is high ($10-$20,000 per acre), due no doubt to the engineering needed to deal with 60,000 lbs per acre weight. Add up the trunks, branches, leaves, fruit and get a big rain, well, that’s a challenge. The green and golden kiwifruit impact on the global market place is exciting. It’s a new crop that has succeeded. Increasing market share is a global kiwifruit talent in the last few decades. Part of industry growth is simple economics and having tasty fruit in front of consumers.
THE GENUS ACTINIDIA: There are over 60 species of Kiwis in southeast Asia. While native to China, New Zealand can be given credit for introducing the fruit to the global marketplace in a big way. Commercially, the green kiwifruit (Actinidia deliciosa) dominates world production and has an interesting history in the global market place. Golden kiwifruit (Atinidia chinensis) are a relative newcomer and production is growing at a very fast clip. Demand continues to increase. There’s another market kiwifruit, Actinidia arguta, the kiwiberry which is smaller, smooth skinned and lacks the storage ability of green or golden kiwifruit. It’s sweet but has a short shelf life. For the serious student, Dr. Huang Hongwen’s 2014 publication, “Kiwifruit: The Genus Actinidia”, is the definitive text. With over 313 pages, it’s an intense coverage of the genus (Science Press Beijing; ISBN: 978-0-12-803066-0).
KIWIS IN CHINA: I have been working short term consultancies in China since 1997. Most of my work is focused on the Taxodium Improvement Program (baldcypress) at the Nanjing Botanical Garden with Professor Yin Yunlong’s team, and the Blueberry Research Institute program of Professor Yu Hong and retired Professor He Shanan. Over many years we have become fast friends and I have been witness to the dynamic growth of China’s nursery and blueberry industry.
Over the years, I had seen Kiwifruit plantations and had some interest but it wasn’t until our first crop of golden kiwifruit at SFASU that my interest was boosted. I wanted to visit the kiwifruit program at the Hubei Fruit and Tea Institute and during an Aug 2015 visit, Yu Hong made it happen. My host was Dr. Lei Zhang (English name ‘Jane’). Jane is a high energy young scientist who recently coauthored a publication on the genome Actinidia (kiwi) in Nature Communications in 2013. I remarked at our first meeting that after such an accomplishment at such a young age, the administrators would only be satisfied now if she came home with the Nobel Prize. Everyone thought that was hilarious – and probably true. In addition to cultural studies with kiwi, she had an active breeding program in place with twenty advanced selections in final evaluation stage and many others further down the pipeline. While at the Institute, we met with Zhongqi Qin, Director of the Institute, who provided us with gracious hospitality and a tour of the research farm. I enjoyed meeting Professor Yang Fuchen, who works with blueberries and pears, and it was great to see healthy blueberry plants in his studies.
While at Hubei, I learned that our two Auburn-introduced varieties, Actinidia chinensis ‘AU Golden Dragon’ and ‘AU Golden Sunshine’, were actually named ‘Jinnong’ and ‘Jinyang’ in China. Jane told me that ‘nong’ pronounces similar with ‘long’ which means ‘dragon’ in English, and ‘yang’ means sun and sunshine. Both were selected in the 1980s, after an extensive field investigation which began in 1978. ‘AU Golden Sunshine’ was selected from the wild in September, 1982, in Chongyang country and was then grafted in the garden in Hubei. ‘AU Golden Dragon’ was a large fruit taken from a distillery and the seeds of that fruit sowed. The seedlings bore fruit in 1985 and ‘AU Golden Dragon’ was selected from that population. The golden kiwi, A. chinensis, is less popular in China than the green fleshed varieties of A. deliciosa, except the variety ‘Hongyan’, which is red fleshed with a short shelf life. She was surprised that I thought eating the skin of the golden fleshed varieties was fine. Of course, this is a country where citizens often peel grapes.
Professor Yu Hong and I also made a visit to the Wuhan Botanical Garden. This germplasm repository is home to over 50 Actinidia species, 81 varieties and over 1000 genotypes, many from the wild. Plants were in good shape, the irrigation system was in fine form and harvest was about a month away.
Over many visits, my general observations is that Chinese growers like to use raised beds, build a strong infrastructure with concrete posts and high tensile wire. They know what they’re doing. Growers prefer a well drained condition for the plant; raised beds and berms are typical.
VARIETIES: The varietal picture for golden kiwifruit in the Gulf South is rather simple – and sparse. There are essentially three female varieties and one male variety with considerable promise at SFA Gardens. We need more. Dr. Hongwen Huang was a PhD student at Auburn (1990-1994) and provided the original cuttings of ‘AU-Golden Dragon’ and ‘AU-Golden Sunshine’ to Dr. Joe Norton, his advisor during that period. After a very productive career as Director and Professor at the Wuhan Botanical Garden, he is currently the Director of the South China Botanical Garden. After several years of fruiting, Auburn University and the Hubei Institute of Fruit and Tea signed an agreement, the two varieties were patented in 2007 and plants are on the market, albeit there have been a few issues on availability and pricing. For those interested, the Gold Kiwi Group has a website that describes product and availability of the two patented varieties that have performed well at SFA Gardens: http://growaukiwi.info/contact.htm
The production data from our small research plot is below.
HARVEST CONCLUSIONS: In the SFA research plots, there appears to be a correlation between chilling hours and yield. We are also convinced there is only one male variety (CK3) functioning as an effective pollinator. ‘Tiger’ and ‘Author’ exhibit poor flowering. It’s fortunate that the flowering of ‘CK3’ coincides with the bloom period of ‘AU Golden Dragon’, perhaps explaining the good yield of that variety. ‘AU Golden Sunshine’ is slightly later flowering and misses some of CK3’s floral strength, catching it as the flowers wane. With that in mind we decided to hand pollinate. in 2018, pollen was flown in from Doug Phillips, a California grower, the effort facilitated by Ross Stevenson of Miko Asia, Ltd. Ross is a New Zealand kiwifruit grower with production in Chile and other countries and is perhaps interested in expanding his efforts into East Texas. In 2018, flowers of both Golden Dragon and Golden Sunshine were hand pollinated and both varieties produced a fine crop.
CONSUMER SURVEY: The general consensus is quality is good. For the 2015 harvest of ‘Golden Dragon’ fruit, over 60 participants were given a bag and a survey form. On a 0 to 10 scale (with 0= horrible and 10=fantastic), the crop came in at 8.84. In our original planting, we have three female varieties, ‘AU Golden Dragon’, ‘AU Golden Sunshine’, and ‘Au Fitzgerald’ coupled with three males ‘CK3’, ‘Tiger’, and ‘AU Authur’, respectively. AU Golden Dragon’ has been the high performer at SFA probably due to its close proximity to the great flowering of the male ‘CK3’. As part of the 2018 crop, we undertook a Consumer preference survey with 110 respondents that yielded the following information: 1) only 21% had ever eaten golden kiwifruit. 2) on a 0-10 scale, golden kiwifruit averaged 8.72 on an overall quality index. 3) 83% who ate golden kiwifruit thought eating the skin was fine. 4) 72% preferred golden kiwifruit over green. 5) 96% said they would buy the fruit in the grocery store. Our conclusion here is that our golden kiwifruit crop passed muster.
ROOTSTOCKS: For a Texas industry to develop, it’s generally accepted that golden kiwifruit need to be grafted on an accepted rootstock. Most commercial plants are grafted on A. deliciosa, in particular. While this has to do with resistance to diseases (Psa, in particular), there’s perhaps another reason in support of rootstocks. By grafting golden kiwifruit to a green rootstock, the resultant vine is less vigorous than on its own roots, thus there are fewer hours pruning and training. While SFASU planted rooted varieties of golden kiwifruit and they have performed well on their own roots, it is still the general consensus that using a rootstock is advisable. We are taking that tact. In 2017, Ross Stevenson of Miko Asia, Ltd., sent seed of “Bruno’ to the SFA Gardens. ‘Bruno’ is a green kiwifruit variety often used as a rootstock. Seed was germinated and 4000 plants potted at the SFA Gardens greenhouse. Plants were transferred to one gallon containers and grown through the winter (Dec 2017-Mar 2018) in an outdoor nursery.
Young kiwifruit plants are more susceptible to freeze injury in the first few winters but older plants are quite tolerant of temps into the low teens and even single digits. In January 2018 a very hard freeze (two nights at 10oF) killed almost 50% of the 4000 plants, in spite of being covered with pine straw and frost fabric. The remainder recovered well and have enjoyed a vigorous growing season. Over 2000 healthy plants are being prepared for the winter ahead and will be planted in cooperator fields in March 2019. These plants will be grafted to improved varieties of golden and green kiwifruit beginning in 2020. Related to the rootstock project, we have received notification that seven cultivars of green and golden kiwifruit varieties (a Miko Asia, Ltd. introduction) will be released from USDA, Beltsville, MD quarantine to our Texas program and a cooperating farm in California in February 2019. Those plants will be multiplied at SFASU and TAMU to provide scion wood for grafting to the rootstocks set in the field.
SPACING: Vines should be very long lived. The first consideration is whether to go high density or not. If growers are interested in higher returns during the early years (years 3-5), then a closer spacing is in order. For high density, the strategy we recommend is that rows should be 12′ apart and plants should be 9′ apart in the row (403 plants per acre). As a high density orchard matures, every other vine can eventually be removed. A final density would be 18′ apart in the row (201 plants per acre for the final density of the orchard).
PLACEMENT OF POLLINATOR PLANTS: Placement of the male pollinator plants is important. Generally, one male plant per 5 to 8 females is considered average. Male branches can be grafted high on the females and marked so they can be pruned accordingly after flowering. There are all female orchards with pollen brought in and applied by hand, via airblast with air or water as a carrier. It’s relatively easy to tell males and females apart. The male flower has robust anthers but the pistil is rudimentary, dies away and often leaves a black lesion. The female flower has anthers but the pollen is sterile and there are multiple pistils present.
FERTILIZATION: There are few fertilization studies with kiwifruit in the deep South. Our experience lends itself to light applications of a complete. We have not fertilized our older vines for several years and they remain quite vigorous.
INFRASTRUCTURE: A strong pergola or arbor is required. The infrastructure needs to support a total weight of at least 60,000 lbs. per acre (vines, branches, leaves, rain and fruit). End post assemblies must be substantial. Line posts are less problematic but wind issues must be considered. The wire must be high tensile strength with little stretching. and is the main support for the arms of each vine.
PRUNING AND TRAINING: Whether high density or not, the structure of the vine is best as a single trunk to 6′ tall that ends with two arms running laterally. This will be the permanent feature of the vine. From the two arms will emerge shoots that should be trained to be the fruiting arm for the next year.
WINTER FREEZES AND SPRING FROSTS: We have learned the hard way that young vines are susceptible to low winter temperatures if they fall below10oF. Once flowers open in late March and early April they are, of course, susceptible to very late frosts. Fortunately, kiwifruit bloom late enough to avoid most spring frosts (i.e., peaches characteristically bloom two to four weeks earlier). Sprinkler systems for frost protection can be designed to protect vines into the low twenties.
A unique problem that has arisen with Kiwifruit is the tendency not to slide into dormancy gracefully. 2018 has been a real benchmark in some respects. Before we had our first frost, we experienced in early November 2018 a first freeze in Nacogdoches, TX, which was quite harsh with two nights a 27F. While our young container plants were unfertilized since July and placed under a lower watering regime, they still appeared vigorous before the freeze. At College Station, Texas, the research plots saw temperatures to 24.7F and damage was more severe on the young vines there. Winter freezes at Auburn and at the GroAuKiwi field have damaged young vines. This reality suggests that young vines need winter protection for the first few years in the field. We have gone to a chicken wire tube stuffed with pie straw.
TEEPEE SYSTEM: For maximizing production, growers in New Zealand have pioneered the teepee system. This system encourages shoots from the arm to climb strings on a teepee. The next winter, those long woody shoots are “laid down” over the wires of the pergola and clipped to create a roof one BRANCH thick. In the spring when growth resumes, the grower chooses shoots from the arm again and trains them to a teepee. So at any one time, there are young shoots clambering up strings, as well as a horizontal layer of shoots that were laid down in the winter. The cycle repeats.
PESTS AND DISEASES: Psa, Pseudomonas syringae pv. actinidiae, is a bacterial disease and no doubt the biggest threat. The introduction of (Psa) severely damaged the New Zealand kiwifruit industry which recovered quickly with a rigorous sanitation program and the introduction of several disease tolerant yellow-fleshed varieties. While Psa has not been found in the Gulf South, the general feeling is that it will arrive. Golden kiwifruit is considered more susceptible than green, thus the recommended use of a resistant rootstock. As for insects, scale has been a problem on a few of our older vines but is easily controlled with a dormant oil spray. Our crystal ball suggests that the Brown Marmorated Stink Bug (BMSB) is a looming threat. It was a major problem in the 2018 Alabama harvest. There have been occurrences in Texas so it’s probably just a matter of time. The Spotted Wing Drosophila is another pest new to Texas and it may be a severe problem in the years ahead. One dilemma for growers is that so few pesticides are currently labeled for Kiwifruit – simply because it’s a new crop and there has been no acreage of impact here in the Gulf South.
TEXAS DEPARTMENT OF AGRICULTURE GRANT. Since 2016, this project has been substantially funded by a Texas Department of Agriculture Specialty Crops Block Grant. We are excited to be working with Tim Hartmann and colleagues at Texas A & M University as they ramp up evaluation and research plots. In the next few years, we’ll know if kiwis are an exciting new commercial fruit for Texas – or not. Even if they’re a go in scattered small farms of the South, I’m convinced there’s a potential bigger opportunity available – one that capitalizes on mass markets and wholesale/retail nurseries to supply plants to homeowners. In the next two years there will be a transfusion of new potential varieties. Never underestimate what good gardeners can do with the right plant material. In the spring 2019 we will be planting four new cooperator sites (Two in the Mt. Pleasant area, Tyler, and Simonton, Texas).
After visiting California kiwifruit growers, we can count a few comparative advantages in East Texas: Land Cost, no need for overhead shade or fogging, Irrigation water is often readily available at low cost, and perhaps labor costs are lower. Disadvantages would include no history of production, processing or marketing and the unknowns of low chilling and spring frosts. Issues with pollination appear important to the long term success of plantings. In the next few years we will have the answers. Until then, we’ll keep planting and studying this fascinating new crop in Texas.
SFA Gardens and the USDA released ‘Earlibirdblue’ in 2011. It’s a southern highbush blueberry recommended for use in homeowner plantings. This variety, tested as MS 108, resulted from a cross of G144 X US 75 made at Beltsville, Maryland, and selected by Arlan Draper and James Spiers in 1979 at Poplarville, Mississippi. G144 resulted from a cross of 11-93 (Jersey X Pioneer) X Darrow and US 75 originated from a cross of Florida 4B (native V. darrowii clone) X Bluecrop. The original seedling of Earlibirdbllue was propagated and established in field trials in AL, MS, and TX in the mid 1980’s to early 1990’s to evaluate performance. Earlibirdblue was evaluated in test plots at Mill Creek Blueberry farm near Nacogdoches, Texas for over twenty years.
Earlibirdblue was released in 2011 (HortScience May 2012 vol. 47 no. 5 536-562) and the description was as follows: A garden and landscape southern highbush blueberry suited to Texas conditions. Origin: USDA-ARS, Poplarville, MS, USDA-ARS Beltsville, MD, and Stephen F. Austin State University, Nacogdoches, TX by S. Stringer, A. Draper, J. Spiers, and D. Creech. G 144 x US 75; crossed 1977; selected 1979; tested as MS 108; introd. 2011. Fruit: medium; good color and flavor when allowed to hang for several days after turning blue; skin may tear at the base of the pedicel, making this cultivar unsuitable for shipping. Plant: moderately vigorous with a relatively short stature, 1.5–2 m; spreading growth habit; attractive, dense, green foliage; consistent productivity; easy to prune and easily integrated into the home landscape; ripens 4–8 weeks earlier than many rabbiteye blueberry cultivars; flowers develop and bloom sufficiently late to avoid most frost damage; chilling requirement ∼500 h; propagation from softwood or hardwood cuttings.
Plants of ‘Earlibirdblue’ are moderately vigorous with a relatively short stature (4-5 ft.), have a spreading growth habit, attractive dense green foliage and are consistently productive. The relatively low plant height produces a shrub that is easy to prune and is easily integrated into home landscapes. In the gulf coast region of the U.S. ‘Earlibirdblue’ ripens early with a fruit ripening period of early to mid May, which is four to eight weeks earlier than most rabbiteye blueberry varieties grown in the region. Although early ripening, ‘Earlibirdblue’ flowers develop and bloom sufficiently late to avoid most frost damage and associated yield reductions.
There are a couple of reasons this unique variety was released as a homeowner variety – and not a commercial variety. ‘Earlibirdblue’ really needs to hang a little longer on the bush than other varieties to fully sweeten up. Berries are tart if picked too early. In fact, prior to releasing this cultivar, there was some resistance to the release. In fact, I remember Arlan Draper suggesting we name it Texas Tart – which is not exactly the best name for a blueberry. Commercial growers are quick to harvest berries the moment they’re “blue”. ‘Earlibirdblue’ needs to hang on the bush a few extra days to truly sweeten. Plus, when picked there’s a slight tear problem at the base of the pedicel – and that could be a serious commercial issue but it’s not that important for the homeowner. The bottom line is that we now have a short stature, very early ripening blueberry variety that has produced well consistently for the past twenty years in our region.
One reason for Earlibirdblue’s consistent production is that it doesn’t bloom that early. In fact, here’s a long ago (03-29-2010) image of the plant at Mill Creek Farms which shows the shorter stature and the lateness of bloom which helps the variety avoid a late frost.
The exact chilling requirement of ‘Earlibirdblue’ is estimated to be approximately 500 to 550 hours less than 45F. Although ‘Earlibirdblue’ may be somewhat self-fertile, productivity of southern highbush blueberries are enhanced when bushes are interplanted among other southern highbush cultivars having a similar bloom period. When planted in rows, plants of ‘Earlibirdblue’ should be spaced 5-6 feet apart in well-drained soils of modest acidity, and plants benefit by a generous application of pine bark mulch, particularly in the early years of establishment.
‘Earlibirdblue’ is expected to be a valuable addition to blueberry cultivars grown for utilization as part of an edible landscape.We recommend that homeowners situate ‘Earliirdblue’ plants in full sun and provide for strong drainage for the root system. A good sandy loam with composted pine bark fines or peat moss mixed into the top 1′ of soil and then mulched a few inches deep in pine bark. If possible, plant in a raised bed. While daily drip irrigation during the dry season is recommended, timely sprinkler irrigation is equally beneficial.
Scuttelaria suffrutescens, the pink-flowering skullcap from Mexico has surprised Southern gardeners with its charm and durability. This is a neatly mounding sub-shrub to two feet tall and about that wide with fine leaves and twigs. It’s a bright pink addition to the front of any border or as specimens massed. P.C. Standley describes the type specimen from Coahuila, Sierra de la Silla near Monterrey, as a small shrub. While more popular in the gardens of central and west Texas, this plant deserves greater use in the dry, sunny gardens of East Texas with Zones 8 and 9 most suitable. We have found that good specimens always elicit some kind of urge to pet the plant – probably because the mound appears and happens to be very firm to the touch. The plant has a bright show in May and early June and the blooming period persists throughout the summer and fall under decent horticulture.
There are a number of pink-flowering forms of this species now appearing in mostly western nurseries but the form that we are displaying in the Arboretum carries an interesting history. It was found during an expedition to Mexico with Lynn Lowrey and Ray Jordan in October 1987. From the Friends of the Arboretum Newsletter # 5, the chronicle of an expedition to the San Madre Oriental mountains I wrote that, “after backtracking east to the main road that runs between Montemerellos and Monterrey, we made one last side excursion to Chipinque. The entire log of that trip can be found here:
. . . and I just noticed that some of the pages are out of order! To be corrected later. The mountain town and associated forest is home for thousands of Mexican redbuds, numerous oaks, and a forest floor of salvias and penstemons. On one hike, a large-flowered Phaseolus vine was spotted, and, according to Lynn, the best find of the trip, a skullcap colony, Scuttelaria species. This rhizomatous, perennial herb made a strong attractive ground cover in a few sun-lit forest pockets.”
Actually, as I remember the find, I said, “Lynn, what’s that plant with the pink flowers,” and Lynn responded, “what flowers?” Amazingly, I came to learn that Lynn was red color blind and could only discern reds, pinks and greens at close distances.
This particular trip had as a goal primarily the collection of oak and other fall seeds; in the case of the Scuttelaria, a few cuttings were taken and rooted easily at SFA. We have found that propagation is easy any time of the year with mist and plants should be moved soon after the first root initials make their appearance. Leaving cuttings in mist after rooting too long can result in dead cuttings.
This is full sun plant for the South and should be give sharp drainage. A raised bed is perfect. In the Arboretum, we have had good success with dry-loving plants by using sandy loam berms and a thin layer of crushed decomposed granite as a mulch. The plant responds to fertilizer. Some attention should be given the plants during the first two establishment years and we have not found the plant to be particularly rhizomatous, behaving instead like a green stiff mound throughout the year. Most surprising, the plant survived the December 1989 dip to zero degrees F at SFA Gardens.
In a recent conversation with Tim Kiphart, SFA Horticulture alum, I learned the following. In 1990, Tim and Pat McNeal, Horticulturist from Austin, Texas, returned to the very same location as our original find. From a batch of seedlings, Tim selected a deeper pink/rose colored form and he later provided Tony Avent of Plants Delight, Raleigh, NC. The only cultivar name I’ve ever seen is ‘Texas Rose,’ a name coined by Tony Avent. Tim feels that seedlings result in better plants with better form than cutting grown. Cuttings do root easy and grow off well. As a small globe here and there, or as a very low statured ground cover, this is an interesting plant useful in the dry landscape.
Sometimes I think we might be better students of history. Right now, the big item in the American news scene is we need to build a big, beautiful wall between our country and Mexico and Mexico needs to pay for it. The whole conversation brings back a memory. Almost twenty years ago I was scrambling in the forest at the base of the Ming Great Wall in Nanjing, China. Now, this is one serious wall. The average height of the wall is about 40 feet with a width of 24’. In its original form, the wall ran about 22 miles and it took 200,000 laborers 21 years to build way back in the 14th century. The top of the wall was wide enough to support an army and I can imagine the poor plight of folks trying to climb up and over the wall with a barrage of arrows, spears, giant rocks and giant pots of boiling oil raining down. It was meant to protect the city. It eventually failed, of course.
Professor Yin Yunlong of the Nanjing Botanical garden, now a longtime friend and kindred spirit, had asked me if we could take a look at a new problem on the wall. We had stopped on the road below and scrambled through the forest to the base of the outside face. It seems there was a fast growing vine that had taken over a stretch of the wall, its tendrils and roots invading the seams of the giant carved stones that made up the wall. The wall was being degraded. It didn’t take long for me to recognize that the culprit was an old American friend, Campsis radicans, our southern USA native trumpet creeper. This wasn’t the rarely-encountered Chinese species (Campsis grandiflora) with larger flowers and a less rambunctious nature. No, this was our southern USA native. I can remember Yin remarking, “Dave, how do we kill this terrible noxious weed?” Without thinking, I said “Hey, this isn’t a weed; this is a cool American plant!” Thus I arrived at a narrative I use to this day. My native is good. Your native is bad. Some call it elitism. Others call it discrimination.
Campsis grandiflora is different. It’s less of a thug. With outlandish orange-salmon-yellow flowers to fully three inches wide, this bright petunia-on-a-stick will shock and amaze. Actually, after we first started growing the Chinese trumpet creeper at the SFA Gardens, I would get more phone calls on this species when it was in bloom than almost any other vine in the Arboretum. Here in East Texas, flowering comes on in a surge in late spring and early summer, lasts a month, and then throws a few flowers off and on for the rest of the year, depending on the degree of pruning and training. JC Raulston of NCSU was a fan and I think we received our very first plant from him. I’ve seen it here and there in the South but it’s never really seemed to catch on. Actually, most of the large flowered Campsis encountered are really the hybrid of our native C. radicans X C. grandiflora, which have been exploited and promoted – some even sold as C. grandiflora.
The simplest way to separate the two trumpet creeper species and their cross is by carefully looking at the calyx (all of the sepals, or the outermost whorl of the flower): Chinese trumpet creeper features a greenish calyx with long, pointed lobes; the American trumpet creeper enjoys a darker calyx with shorter lobes that aren’t quite pointed; and the cross lies in between.
Much less invasive and obnoxious than our native C. radicans, C. grandiflora is often difficult to root especially if adult wood is used. Once rooted, the plant is also tricky to time flowering in the container. If young, vigorous juvenile wood is rooted, it can take a while to see flowers. They’re unpredictable. Looking at a sea of non-flowering Chinese trumpet creeper is not exactly what the nurseryman has in mind. Now, there is a cross between the two and the hybrid is often referred to as Campsis X tagliabuana, most often represented in the USA nursery industry as ‘Madame Galen’. This trumpet treeper features a large, showy bloomy often orange to red that appears in summer. There are other varieties.
There’s another dilemma and this further complicates the picture. C. grandiflora is self-sterile. That is, until we can find “wild” Campsis grandiflora in China and bring in a good number of seed or seedlings, it’s going to be hard to improve the species. The original Raulston clone is the same clone as the old clone in Florida and the old clone in Texas. Being self-sterile, there’s no opportunity to explore the diversity in the species. A bummer. So, on a return trip to China years ago, I made the ask. Evidently, it was thought to have disappeared in the wild – and all the Chinese trumpet creepers in Chinese landscapes are one clone. Well, Professor Yin said he finally located some seed. I was elated. They arrived out of USDA quarantine. I grew them for a year or two and then planted them in a long row along a fence. In a year they bloomed. ALL C. radicans, and not a particularly superior form at that. My breakthrough was now a breakdown. The saga continues.
Our native is often cursed for its invasive nature. I’s a swallow your house kind of thing. It suckers and sneaks around in the dark to emerge here and there. Eternal vigilance is the order of the day. If trained properly, however, and put in the right spot, it can be controlled. I saw a nice plant in Little Rock, Arkansas that had the situation whipped. The vine was planted in a crack between a sidewalk and a large building. Beautiful treatment.
I planted a yellow form of our native in what I thought was a good spot. It couldn’t escape and I just had to remember to return ever few years to whack it back. It worked for years until I returned and noticed the business had killed it. Struck me as a brilliant strategy. Obviously the 2 mph speed bump sign didn’t slow the species down.
In a battle to the death, our USA native can take the Chinese form with one shoot tied behind his back. It’s not even a fair fight. It’s Texas tough, showy, a heat lover and if you wait a few hundred years, you can have something folks will marvel at.
There’s only one Anemone that’s been bulletproof for us in East Texas. Years ago I was sauntering in the landscape of Alice Staub Liddell, a past-President of the Houston Garden Club of America. There’s a garden named for her on the campus of Rice University. Alice was a Houston socialite, philanthropist and friend. She was a close friend of Lynn Lowrey and we actually travelled together for several weeks in the mountains of Mexico in the 1980s. In her garden, I spotted an Anemone that Lynn had given her for safekeeping and I was quite impressed. While I had long admired the species, I had trouble getting them to thrive in East Texas. They would grow and flower but seemed to slowly decline over the years. I asked if I could divide the plant and she said, yes, of course. At SFA, the plant thrived and we passed it around here and there under her namesake. I’ve concluded it’s quite heat tolerant. I think it’s a hybrid and the official epithet would be Anemone X ‘Alice Staub’.
Taxonomically, Anemone × hybrida Paxton is normally considered a hybrid of Anemone hupehensis var. japonica and Anemone vitifolia, but, to be honest, I’m not sure from where ‘Alice Staub’ was originally derived nor it’s early history. I do remember Alice remarking it was one of the only Anemones she had found to do well in Houston soils and climate. There’s a clone that can be found in various mail order nurseries called ‘Alice’ and it may be the same. It forms large mounds of dark green interesting foliage and features 2-inch pinkish blooms on stems to three feet. It does run a bit cheerfully in the garden and appreciates morning sun.
Time passed and over a decade ago I gave a few to Janet and they prospered at her home in Shreveport. Years later I wanted to propagate it and I couldn’t find the plant at the SFA Gardens. I assumed it was extinct at SFA. I asked Janet if I could divide her plants and she acquiesced just as long as I promised I would bring her back some plants. I brought a bag of small plants back to SFA and remember turning them over to Dawn. Dawn denies that. She could be right. Before I knew it, I was Anemoneless. Janet never forgets anything and after some time began to ask, where are my plants? I said they are in process. Fortunately, Dawn finally recognized that my marriage was now in trouble. She found the plant somewhere in the garden, propagated plenty and we were back in business. The plant will be featured in the Spring 2018 plant sale and my marriage is back on track.
Anemones are interesting plants. There are over 200 species in the Ranunculaceae and they are generally native to temperate regions. Robert Fortune introduced the plant to England in 1844 from China, where he reported it was often found planted around graves. Anemone are appropriately called “wind flowers” as they sway on long stems in the slightest breeze. Jeff Abt, who just retired as the garden writer for the Nacogdoches Daily Sentinel really liked this plant and recognized it as a fine perennial in one of his long ago columns. Heidi Sheesley of TreeSearch Farms in Houston may be a sole nursery source and Heidi reports it’s the only Anemone that can perform in the heat and humidity of Houston. Dawn has featured the plant in our SFA Gardens plant sales and she deserves kudos for resurrecting it and bringing it back into our Nacogdoches family.
Magnolia pyramidata, the Pyramid magnolia, is a very rare tree, and in Texas it’s restricted to the eastern counties of Jasper and Newton in deeply wooded sandy ridges. You can tell it from southern magnolia and sweet bay by the deciduous leaves, about 9 inches long and 4 inches wide, with earlike lobes at the base and whorls around the stem. The terminal flowers are white and fragrant and the rosy-red seed pods are two and a half inches long and longer. To grow successfully it needs acidic, sandy, moist soils and at least a little shade. It makes a nice small tree and the seed pods are a real plus in late summer.
It calls home the rich woods and river bluffs, mostly in the coastal plain, sometimes lower piedmont. Never abundant, it is found in small colonies in Alabama, Florida, Georgia, Louisiana, Mississippii, South Carolina and Texas.
Magnolia pyramidata differs from the allopatric M. fraseri in being a smaller tree with a narrower, pyramidal habit; M. pyramidata is very local and nowhere abundant. Morphologically, M. pyramidata differs from M. fraseri in the pandurate leaf blades, smaller flowers and stipules, fewer stamens and pistils, and smaller follicetums. Magnolia pyramidata is occasionally cultivated, but it is less hardy than M. fraseri.
Seed are easy to germinate if not allowed to totally dry out. A month of stratification is sufficient.
In the last year, we have enjoyed hosting a number of botanists to the East Texas population. These expeditions are adventures in the special places of East Texas. We are unsure of the record tree, but an old report suggests that the largest known tree of Magnolia pyramidata may be in Texas. Over twenty years ago, this tree was 11.9m in height with a trunk diameter of 69 cm, was recorded from Newton County, Texas (American Forestry Association 1994). We will get it remeasured. In an expedition in August 2016, Keith Stephens led a motley crew of botanists, including Darren Duling, Greg Paige, Andrew Bunting, Peter Loos, Jerrel and Darrel Durham and others to the big tree on Campbell land. I am still looking for the circumference data and will post later.
Emma Spence of the Morton Arboretum visited East Texas and collected tissue samples for DNA analysis. She was on the final leg of an across the South expedition to gather tissue from the different populations across the South. She was unable to find ANY wild populations left in Louisiana and it was apparent that development has taken a toll in our sister state to the East. The East Texas population is on Campbell Group land and Keith Stephens was wonderful to show us around with Emma. She was quick to announce that the colony population was greater than any of the sites in states to our East, estimated at over 1000 plants.
For now, the champion tree is in Florida and in 2010 enjoyed a 68″ circumference and a height of 102 feet with a crown spread of 39′. Good friend Richard May was the finder of this amazing tree near Gadsden, Florida and took a couple of images for us to share. I now have pyramid magnolia envy.
Vitex rotundifolia – Is beach Vitex a beauty or a beast? Good grief! Isn’t this an invasive species? Isn’t this the dreaded “Kudzu of the beach” now threatening the Carolina dunes? Isn’t this the focus of all kinds of eradication campaigns? Why would any serious horticulturist even talk about a plant like this, much less write about it? Well, we’d just like to quietly point out that there many areas of the southern USA where it’s quite common in landscapes – and it’s simply just another interesting non-invasive exotic plant. That’s the case in our region of Texas. With over thirty years of experience with this hardy evergreen species in the USA – it’s an immigrant from Hawaii, believe it or not – we can now say there are many parts of the South where beach Vitex is rather tame. This is a species grown in fairly large numbers from a wide range of wholesale nurseries in Texas, Alabama, and Louisiana. Considering the fact that this is one tough immigrant from Hawaii, and the fact it’s easy to keep alive, it shouldn’t surprise anyone that it appears here to stay. Given a little positive horticulture, the plant can be downright beautiful, and it’s in that vein the plant can be used.
First, let’s give testimony and respect to the species as a landscape candidate, without discounting its invasive potential in areas where it finds itself too much at home. Writing this piece conjures up memories – twenty years ago – of some officials of the U.S. Fish and Wildlife Department visiting J.C. Raulston, Director of the North Carolina State University Arboretum, and suggesting to him that promoting, growing, thinking about or touching this plant was just about the most horrible thing a horticulturist could do. Yes, this plant is easy to grow. In coastal sandy spots, it can go where you don’t want it to, and when it’s there it can and will smother native vegetation. It can be a bad boy. So here’s the rule: In those sections of the country that beach Vitex is way too frisky for its own good, don’t plant it, and, when you see it, kill it. In our Zone 8 region of Texas, we have never seen a seedling . . . and if landscapers used the plant as described in this treatise, well, the end result is no problem. As a groundcover in our region, beach Vitex is not that voracious. At the San Antonio Botanical Garden in Texas (a bit warmer than Nacogdoches, Texas in the winter and summer), Paul Cox reports that it’s “manageable”. Knowing Paul Cox, that might not be too good. At any rate, experience is a good teacher.
First, how bad is this plant? Well, it is a native of the USA, but only because it comes from Hawaii. First introduced as an exciting groundcover over 30 years ago as a potential groundcover for sunny dry spots, this introduction made its way to the sand dunes of South Carolina, and it’s there that beach Vitex has come to be quite frightening. This brief note isn’t intended to stir up a fight in the horticultural crowd. The invasive exotic issue is real and one that deserves respect and attention. We know that. However, an invasive in one spot can be quite docile in another and it’s in that vein this article is presented.
If you happen to live in a region of the USA where beach Vitex never throws seedlings – and where it’s easily managed in a run – the plant does have attributes. We have long enjoyed it as a vine in our “line of vines” collection. The foliage is beautiful, clean and fully evergreen. The blooms are relatively inconspicuous coming in the fall as blue spikes. While attractive up close, they are never overwhelming. Our most conspicuous specimen in the Mast Arboretum “line of vines” was trained to a post and never failed to gain approval by visitors. We had evaluated this plant for over 20 years. Unfortunately, with some misunderstood directions, this old specimen was cut to the ground and destroyed by well-intentioned staff. A lost but not the end of the world. We’ve used the plant as a vine and as a groundcover and found that it responds to an occasional shearing. Once again, let me repeat, we’ve never seen a seedling in our Zone 8 garden (not that we won’t find one tomorrow!) –
As far as we’re concerned the Chinese evergreen dogwood is one durable plant. It’s been a surprise here in East Texas for over two decades. Given a little soil drainage and some protection from the western sun, it develops into a fine specimen small tree. The bloom show on a good sized tree can be stunning, a cloak of white flowers for several weeks in mid summer. The blooms are followed by interesting sweet red fruits which are edible. While not about to take over the grocery chains in the South, they are good. Extremely useful in a famine my friends in China would say. In our winters the foliage remains dark green with only the harshest winter turning foliage slightly purple. In particularly cold winters further North into Zone 7, the foliage might drop. We have offered this tree for years in our plant sale and most find the tree easy to grow and pest free. This is one of our favorite trees and we highly recommend growing one in your garden!
There is one variety we have in the collection, “Empress of China”. It was selected by the great plantsman John Elsley for exceptional bloom count, beautiful fruit and great garden vigor. It touts glossy, leathery bright green leaves. In theGayla Mize garden we have planted a long line of seedlings of this tree and there are differences here and there but they’re not dramatic. Some seedlings do seem to have better flowers and we’ll continue to see if anything is worth introducing. Right now, it strikes me that seedlings are solid and perform well.
For a mid summer show, this small tree is a surprise. While available, it’s yet to be a market mover in Texas. We think East Texas and across the Gulf South will make a fine home for this tough as nails ornamental.
I’ve concluded that Hibiscus dasycalyx, the Neches river rose mallow, is certainly in danger of being lost in the wild. Intrusion by other mallows seems to favor the invader, whether H. moscheuotis, H. militaris, or H. laevis. Where they comingle come progeny sharing a fairly friendly gene pool. It’s a modest megacharasmatic endangered plant with a neat story. Known in the wild from only four populations in East Texas, it must be noted that the species has found a home in over a dozen reintroduction projects, as well as in Southern Arboretums, botanical gardens and home landscapes. While no barn burner in the market, it has moved into all kinds of horticultural and nursery channels across the South. Along the way, as professional and amateur horticulturists and breeders are known to do, it’s been used to produce a range of interesting hybrids. The long narrow leaves are unique and incorporating that aesthetic into progeny with large red, pink, or white flowers, well, it’s done. Given half a chance, this wetland species will survive in a home landscape. To be totally cheerful, all it needs is a naturally wet site, good sun, and you can’t let the spot grow into a forest.
First a little botany: Hibiscus dasycalyx is a shrubby-appearing herbaceous perennial that grows 0.8-2.3 meters in height. The glabrous leaves are narrow and deeply lobed, and the flowers are white to cream with a crimson throat. The calyx is densely covered with long hairs, and the seeds are densely reddish hairy. The specific epithet “dasycalyx” translates from the Greek to mean a fruit-covering that is “shaggy” or “thick-haired”. Blake (1958) commented that the species is distinguishable from all other United States Hibiscus spp. because of its densely spreading hirsute calyx. An obligate wetland species (Reed 1986), H. dasycalyx is a member of Section Muenchhusia (n=19), a group of five closely related Hibiscus species that are uniquely designated “rose mallows” (Blanchard 1976). The rose-mallows may have evolved recently and all are in floodplain or coastal plain wetland habitats of the eastern U. S., the western boundary being East-Texas north to Canada. Seed dispersal for this group appears to be entirely water-dependent.
Rarity: Ecological and Genetic Status
The four known locations of H. dasycalyx are wetland habitats within floodplain plant communities of large creeks (Houston Co. and Cherokee Co.) and in major river bottoms (Trinity Co.). These plant community types have been termed by Nixon (1985)
as Wet Creek Bottom and River Bottom Communities. Within these communities, Hibiscus dasycalyx occupies open slough and oxbow habitats that experience periodic flooding. The Trinity County site is on the Neches River floodplain and was discovered by Ivan Shiller in 1955. This original site was later designated the type locality by Blake (1958). In 1978, 23 years later, a second population was found by Claude McLeod on Tantaboque Creek, a tributary of the Trinity River in Houston County.
In 1988, when only two locations were known, investigators found that the type locality of H. dasycalyx had already been severely disturbed (McMahan 1988). Paul Cox (1988) and Elray Nixon reported that “all but two plants had been dredged up from an expanded drainage project and were resprouting in a soil bank about three meters above the former water level”. The third documented population on Mud Creek, a tributary of the Angelina River in Cherokee County, was found in 1992 by Jason Singhurst (Carr 1992). It too has suffered over the years (mowing, herbicides, etc.).
In the early 1990s it was noted that all four populations are in serious decline. Surveys performed by TNHP staff and Warnock in slough and oxbow habitats have produced negative findings (Orzell 1990, Warnock 1995). Over the past years, cursory searches have been conducted in potential habitat around highway-river crossings in at least 35 counties. Habitat reduction by drainage and filling of sloughs and oxbows, prevention of oxbow production, and channelization have likely negatively impacted H. dasycalyx populations (Warnock 1995). In addition to habitat reduction, genetic drift appears to be a major threat to this extremely rare species. The two wide-spread and closely related H. laevis and H. moscheutos are found growing in the same or nearby wetland habitats. Apparent hybrids with H. moscheutos have been found at the Trinity Co. and Houston Co. populations. Hybrids with H. laevis have also been noted at the Cherokee Co. site.
Orland Blanchard (1976) conducted thesis research on the Hibiscus section Trionum Sensu Lato in 1976. Blanchard’s research included morphological descriptions, systematics, hybridization studies, and distribution/habitat information for H. dasycalyx. In 1992, Klips hypothesized that H. dasycalyx is a product of diploid hybridization speciation between two wide-spread sympatric closely related species, H. laevis All. (halberd-leaf rose-mallow) [syn. H. militaris Cav.] and H. moscheutos. Klips (1995) studied morphological relationships and conducted electrophoretic screening on the three species and determined that H. dasycalyx is probably not the product of hybridization but perhaps a recent offshoot from the interfertile and morphologically similar H. laevis. The genetic relationships among these three Hibiscus species and the potential for current and future genetic-swamping of the rare H. dasycalyx has been reported (Blanchard 1976, Klips 1995, Warnock 1995). Despite these questions, many investigators continue to recognize H. dasycalyx as a distinct species as concluded in early work (Gould 1975, Correll & Johnson 1979, Nixon 1985). The debate remains.
Research on H. dasycalyx has been conducted by Texas-based agencies and institutions, including the Texas Natural Heritage Program (TNHP), the Texas Nature Conservancy (TNC), the CPC at Mercer Arboretum and at the San Antonio Botanical Gardens (SABG), the Texas Regional Institute for Environmental Studies (TRIES, Sam Houston State University), the Stephen F. Austin State University (SFASU) Arboretum and the USFWS in Houston and Austin. These organizations have reported on the status of survey, habitat and plant vigor, and/or propagation of H. dasycalyx (Cox 1988, Orzell 1990, San Antonio Botanical Center 1990, Smith & Creech 1995). Blanchard (1976) and the San Antonio Botanical Center (1990) have reported successful cultivation of H. dasycalyx. Likewise, Erin Smith, SFASU graduate research assistant, conducted rooting experiments from stem cuttings, seed germination and fertilization trials in 1994 and 1995 (Smith & Creech 1995). Additional stem-cutting propagation and fertilizer trials were conducted by the author in 1995 on cultivated plants of H. dasycalyx. In general, these studies indicated favorable rooting percentages of softwood cuttings under mist with photoperiod interruption.
A variety of ecology research has been published on other rose-mallows. This information can be useful in the formulation of a conservation strategy for H. dasycalyx because of the similarities in habitat niche and reproductive strategy of these species. Genetic affinities between H. laevis and Florida-endemic H. coccineus have been studied by Wise and Menzel (1971), elucidating a lineage with H. dasycalyx. Also important is the fact that all of the rose-mallows appear to be pollinated primarily by Ptilothrix bombiformis Cresson (Anthophoridae), a non-social bee that is a Hibiscus specialist (Blanchard 1976; Spira 1989). Therefore, study of the pollination ecology of other rose-mallows may be pertinent to the understanding of H. dasycalyx’s current status and future chances as a self-sustaining species. Research on the pollination ecology (Spira et al. 1996, Spira et al. 1992), pollen competitive ability (Snow & Spira 1994), selfed progeny vigor (Snow & Spira 1993), seed predation and reproductive success (Spira 1987) has been conducted for the wide-spread rose-mallow, H. moscheutos. In addition, dissertation research is available on the community production and biomass allocation of H. moscheutos (Cahoon 1982) as well as on the distribution, herbivory, and seed set problems of southeastern Hibiscus spp (Cochis 1964; Robbins 1985). Observations from these investigations can guide the development of appropriate strategies for the augmentation of H. dasycalyx at in-situ and ex-situ locations.
Cultivation research has been conducted on other rose-mallows as well. H. moscheutos has been cultivated for ornamental use in the United States since the mid 1800’s (Welch & Grant 1995). For the establishment and maintenance of cultivated H. moscheutos, which is a heavy feeder, an annual application of a balanced fertilizer is recommended (Giles et al. 1980). Propagation and horticultural care information on both H. moscheutos and H. laevis (syn. H. militaris) can be found ubiquitously in gardening literature (Griffiths et al. 1992). The Landscape Restoration Handbook lists these two rose-mallows as native species suitable for introduction into marshy habitats in the Southeast U. S. (Harker et al. 1993). The Handbook provides information on plant type, environmental tolerances, aesthetic value, wildlife value, flower color, bloom period, and landscape use for over 3300 native plant species.
Conservation and Recovery Strategies
Prior to the addition of H. dasycalyx to the Category 1 candidate list, Warnock (1995) indicated that there were no mechanisms for protection of this rose-mallow since known populations are subject to mowing, discing, bulldozing, herbicide use, drainage, genetic swamping from sympatric rose-mallows, genetic drift and, potentially, are subject to over-collecting. Unless the species is listed as endangered or threatened, either at the state or federal level, the remaining H. dasycalyx plants and its habitat cannot be protected or managed for conservation (Warnock 1995).
Listing a rare plant species is not a panacea, however. The 1973 Endangered Species Act (ESA) may prevent the federal government and private citizens from harassing or killing listed animal species on both public and private land, but there are no prohibitions from destroying threatened and endangered plant species by private citizens on private land (Doughty & Parmenter 1989). Since the federal government is prohibited from the extirpation of threatened and endangered plants, federally funded or managed projects are required to mitigate activities to ensure conservation. Because the majority of the known occurrences of H. dasycalyx are found on private land, listing by the federal government may have little effect on the destiny of this species. Listing or not, the key to recovery of this Hibiscus is the implementation of cooperative agreements among federal and state agencies, institutions, and private land owners.
While it was once the priority of the USFWS to explore conservation possibilities that could avoid the listing of H. dasycalyx as endangered (Nemec pers. comm. 1996), the species is now listed. While rare plant management can involve many different methods, there is an increasing need for population re-introduction and restoration to be a part of the recovery plan (Falk 1987). Re-introduction is defined as the intentional establishment of a plant species where it has become extirpated for the purpose of establishing a self-sustaining population (Maunder 1992). In order to implement re-introduction and restoration, cultivation studies need to be implemented. It is obvious that the primary goal of conservation research on a given species is not horticultural knowledge, but such knowledge is necessary to develop techniques for cultivating rare species as a means to an end (Affolter 1997).
For H. dasycalyx, conservation strategies recommended by Warnock (1995) include the cultivation of plants to ensure against catastrophic loss, to prepare for re-introductory work, and to provide for scientific and educational activities. However, Ashton (1987) asserts that genetic viability of remaining populations of rare plants must be estimated before a conservation strategy is executed. This research requires funding. It is unknown when or if H. dasycalyx will be federally listed and when funding will be allocated for genetic viability research and conservation strategy design, initiation and implementation. While genetic viability is being ascertained for any rare species, immediate propagation and development of controlled ex-situ sites can check over-collecting due to potential horticultural value and curb destructive and unethical collection into the future (Mc Cartney 1995). As for H. dasycalyx, it appears that ex-situ preservation measures need to be taken soon since habitat preservation is tenuous for the three existing populations. Species such as H. dasycalyx, which have fewer than five locations, may become extinct if a chance event causes a population crash (Falk 1992). In addition to the threat of continued habitat degradation, Klips (1995) suggests that H. dasycalyx should be isolated from H. laevis and H. moscheutos to avoid dilution by gene flow when establishing preserves. Since hybridization is occurring at all three of the natural populations, this recommendation excludes them as re-introduction sites. In the interim, Mill Creek Gardens can provide a safe ex-situ site for cultivated H. dasycalyx because the site is isolated from all other Hibiscus species. Continued propagation and monitoring would be under the auspices of the Stephen F. Austin State University Arboretum. Since funding for the implementation of conservation projects is affected by federal, state, and industry politics, many plans are not implemented or can occur piecemeal over time. Augmentation via propagation and establishment in ex-situ sites needs to be initiated while waiting for the necessary bureaucratic processes to occur.
RESEARCH PLOTS, NACOGDOCHES, TX
A randomized complete block design (RCBD) was used for this H. dasycalyx fertilizer and mulching trial. Plants were randomly divided into groups of four and randomly assigned to three blocks of eight groups each. 32 plants were planted in each of three blocks, giving a total of 96 plants. Treatments were randomly assigned to 24 experimental units (plots) containing four plants each, with each treatment appearing exactly once in every block. Between the four rates of fertilizer and two mulching regimes, there are eight different treatments per block. The blocks are 6.1 by 12.2 meters (20 by 40 feet). The plots are 3.05 by 3.05 meters (10 by 10 feet).
In September of 1995, 96 plants were selected from several hundred plants using guidelines regarding morphologically correct features for the species. A portion of the H. dasycalyx plants used were stem cuttings taken from a single plant that had been propagated from the type locality and grown at the SFASU Arboretum. The rest of the plants used were progeny of these cutting-grown plants. The seeds were germinated and the cuttings were rooted and grown in the SFASU Arboretum greenhouse; then hardened off in one gallon cans in an outdoor shade house from 1994 to 1995. A selection protocol was followed because putative hybrids with H. moscheutos occur at the type locality. Appendix 3 provides a comparison of morphological features among H. dasycalyx, H. moscheutos, and H. laevis (Warnock 1995).
The fertilization and mulching experiment on H. dasycalyx at the Mill Creek Gardens research site was initiated in October of 1995 and concluded in November of 1996. Two separate applications at four rates of slow release 14-14-14 OsmocoteÒ fertilizer was made during the trial, once during planting (October 18, 1995) and again, approximately one month after dormancy-break (March 21, 1996). The slow release fertilizer is encapsulated within multiple layers of polymeric resin. When water vapor penetrates the permeable shell and dissolves the nutrient core, the resulting osmotic pressure within the granule meters the liquid nutrients through the coating and into the surrounding soil/media (Scotts 1995). 14-14-14 OsmocoteÒ is coated to provide approximately 4 months, based on an average soil temperature of 70°F. Some use can occur in the winter months by an herbaceous perennial such as H. dasycalyx, via absorption and storage in the roots.
The fall application (10/18/95) of the four rates (0, 18, 36, and 72 g) was applied in-ground and as a top-dress (total application was 0, 36, 72, and 144g). The fertilizer was mixed into the soil/mulch directly below the roots as the plantings were made. The top-dress was applied within the root zone (10 cm radius) of the plants. The spring application (3/21/96) was a repeat of the 0, 18, 36, and 72 g rates as a top-dress only. Therefore, total fertilizer application for the study was 0, 54, 108, and 216g per plant. In the dry soil plots “wells” of soil/mulch were constructed around the root zones. In the standing-water plots plastic collars were placed around the plants to hold the fertilizer prills within the root zones. To further avoid intra-specific interaction of root zones and fertilization, the plantings were made at least a meter apart.
The low application rate (54g/plant) is equivalent to applying 12lbs of fertilizer per 100 plants or 1.9 ounces per plant. In terms of pounds per square-foot, the low rate is equivalent to .36 lbs/ft2. For 14% NPK, the low application rate is approximately .05 lbs/ft2 of each of the nutrients.
For plots selected to receive mulch, two gallons were mixed in the planting hole and four gallons of mulch was applied as top-dress around the plant. All holes were dug uniformly to accommodate the addition of mulch. For each non-amended plant, the soil was simply returned to the planting hole with the appropriate rate of fertilizer.
Plants were watered at the end of planting time (10/18/95) and then again on 10/28/95 due to drought conditions. Weed removal was conducted once during the study. In mid September 1996, all plants were removed within a 20 cm radius of each H. dasycalyx, regardless of their perceived threat.
Stacy Scott collected data for three years (1196, 1997 and 1998). Results concluded that mulch and fertilizer (applied at planting) improved plant performance three years in a row.
We concluded fertilizer treatments did help plant growth and long term survival. Mulch did not. What was most interesting is that even though fertilizer was applied only in the first year, the benefits of that application were still significantly apparent three years later. Perhaps the additional growth in the first year allowed the fertilized plants to compete with weeds later in the plant’s life.
RESEARCH PLOT REVISITED IN 2013
Dr. Dave Kulhavy and students revisited the plots in 2013 and mapped the plants. Data collected included plant height and number of stalks per plant.
With this data, Dr. Kulhavy and students placed plants in categories based on stalk number. Because stalk number is some indication of plant size and age, it could be demonstrated that in nearly twenty years, the plants have a fluid presentation across the site.
GENETIC VIABILITY RESEARCH NEEDED
A major issue surrounding the propagation and re-introduction of extremely rare species such as H. dasycalyx is the small number of plants that exist. Would re-introduction involving the propagation of a few individuals (a narrow genetic base) warrant the time and expense of such a project? The CPC (1991) recommends that between 10 and 50 individuals could preserve a significant fraction of the genetic information within that population. As of 1995, the three populations of H. dasycalyx contain as few as several to perhaps no more than 60 plants, and because each of the populations are hybridizing with H. moscheutos or H. laevis, it is likely that this sampling criteria will not be met for this species. Some investigators suggest that dozens of genetic individuals are needed to preserve fit genotypes in progeny (Guerrant 1992; Ashton 1978). However, this assertion may be based on theoretical assumptions or on animal studies and does not necessarily characterized long-term or species-specific plant studies (Eloff and Powrie 1990). New populations of plants are often started by one or several founding individual(s) and have become genetically viable and self-sustaining. One example cited by Eloff and Powrie (1990) involved the establishment of three plants of Aloe spectabilis (Aloeaceae) transplanted in 1900 to a location genetically isolated from any colony of Aloe. The original three plants produced a population whose numbers have increased to about 10,000 plants. These investigators indicate that at least with Aloe spectabilis, three plants were sufficient to establish a self-sustaining population with apparently the same diversity as the original colony.
Even if the CPC’s recommended sampling criteria is met, it is argued that ex-situ conservation of a small genetic sample can lead to unpredictable changes in gene frequencies and loss of gene combinations (Ashton 1978). Some investigators assert, further, that the use of genetically “depauperate” or cloned material will doom a project because of the genetic homogeneity of the re-introduced individuals (Maunder 1992; Gordon 1994). There is no question that artificial augmentation terminates the natural selection process, but is it necessarily true that the use of small samples causes deleterious or undesirable gene combinations? Stebbins (1950) states that, as a matter of course, naturally rare plant species evolve thoroughly exposed to inbreeding and that depression is unlikely to occur. The answer is species and strategy specific. More research is needed in the arena of founder effects and population bottlenecks involving naturally rare plant species before decisions are made to forego conservation of them. An excellent examination of extinction probability and minimal viable population (MVP) regarding the conservation of rare plant species can be found in Conservation Biology (Fiedler and Jain 1992).
Closer to the focus of this research is “conservation horticulture,” defined by Affolter (1997) as the application of techniques and the knowledge base of horticulture to rare plant conservation. The technical aspects of a re-introduction project for endangered plant species must be logistically feasible or the effort is academic (Falk and Olwell 1992). The technical feasibility questions posed by Falk and Olwell (1992) are: Is there enough re-introduction material? Are propagation and transplanting techniques being studied? What are the interim management needs of newly transplanted material? Horticulturists have begun to respond to the concerns of managers who are struggling with the huge task of rare plant management. The International Conference on Botanic Gardens and the World Conservation Strategy (Bramwell 1987) encouraged the involvement of botanic gardens in conservation action; botanic gardens should maintain, propagate and make available stock of threatened species for scientific and horticultural research. The International Conference stated that no single approach to the conservation of endangered species can be relied upon; therefore, ex-situ conservation is a necessary adjunct to in-situ conservation (Bramwell 1987). Given (1987) lists five reasons why botanic gardens and arboreta should grow plants for conservation purposes (p.104):
To have as many threatened species in cultivation as practicable as an insurance against their loss in the wild.
To cultivate critically threatened species in sufficient numbers so as to prevent significant genetic erosion.
To have material available for research and for assessment for economic use.
To have collections of plants available for educational programs and for public displays.
To propagate and maintain plants suitable for use in programs, to reintroduce species into the wild, or to reinforce wild populations.
Since the late eighties, the CPC and the Botanic Gardens Conservation International (BGCI) have instituted standards for documentation, study, and maintenance of rare plant collections at ex-situ sites (BGCI 1993; Wieland 1995).
HORTICULTURAL RESEARCH OF H. DASYCALYX
There is very little information regarding the cultural and maintenance needs of nursery-grown H. dasycalyx for establishment in wildland situations has been published. This information is needed because horticultural treatments, such as fertilization and mulching, may positively affect survivorship, establishment and biomass and reproductive vigor (Poincelot 1980, Vitousek 1982, Merwin and Stiles 1994, Boodley 1996). Plants require an adequate nutrient supply for proper growth, sexual maturity and senescence (Barbour, et al 1987). In the case of some ex-situ habitats, “mitigation” introduction sites, and re-introduction locations which have incurred ground-disturbing activities, soil nutrients may be in short supply or out of balance (Vitousek 1982). Nitrogen is usually the limiting nutrient in many communities, particularly following disturbances. Other cultural treatments such as mulching can maximize growth and availability of essential plant nutrients (Merwin and Stiles 1994). Poincelot (1980) characterizes mulches as the ultimate conservation agent: mulches increase soil moisture retention, mitigate soil erosion, provide a temporary barrier to competition, and mediate soil temperature.
Generally, optimizing plant growth by whatever means, can give the target plant an initial competitive edge over other plants already established in the community. Response of plant vigor in the rare H. dasycalyx during the first year of establishment to fertilization and mulching provides feasibility information for the implementation of ex-situ and re-introduction projects. Equally as important, this study also provides first year anecdotal field observations on inter-specific competition, microhabitat differences regarding moisture regime, and herbivory at this ex-situ location.
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