This is a really dwarf elm – basically a densely branched wider than tall toadstool blessed with a blanket of tiny green leaves. Each leaf is typically elm-like, less than an inch long, and arranged in a closely spaced herringbone pattern along the branches. This unique variety arose as a chance hybrid seedling in a garden in Birmingham, England. While sometimes encountered as Ulmus elegantissima ‘Jacqueline Hillier’, the Royal Horticultural Society seems convinced that this variety was created by a cross of Ulmus glabra and U. plottii. ‘Jacqueline Hillier’, whatever the exact name or parentage, deserves much more use in the landscapes of the southern USA. We have grown the clone for years and have found it to be a conversation piece.
I have encountered ‘Jacqueline Hillier’ as specimens in a number of botanical gardens, arboreta and private gardens in the South, and I’m convinced this is a cute little shrub of considerable merit. There’s a fine older specimen in the Missouri Botanical Garden near the conservatory. The variety is very hardy, reported to survive -25o F (!), and if kept in a conservatory, “Jacqueline Hillier” remains essentially evergreen. In the garden, this variety can be left unpruned to become quite large in a decade or two. On the other hand, careful winter and summer pruning can keep the shrub within almost whatever small volume you desire. Popular in the bonsai crowd, the species can be pot grown quite easily, but again, this is not a plant that one can leave for very long without taking care of watering. In one garden, the proud owner had limbed up the variety to remove the dense branching and expose the bark. While more elm tree shaped, I didn’t care for the effect. The plants seemed unhappy and I concluded it wants to be a toadstool. The branching is unique, a herringbone ambience to its form.
‘Jacqueline Hillier’ appreciates a very well-drained soil and (in our area) needs timely irrigations to keep the plant crisp and clean. Hot dry conditions, particularly for plants sited in full sun, often creates leaf burn. This clone is not tolerant of wet feet and can succumb to saturated soils – and we have lost the plant in several wet locations over the years. While the variety can survive such bouts with drought, it’s not the way to grow the plant. ‘Jacqueline Hillier’ has excellent resistance to Dutch elm disease. Various wilts, rots, cankers and leaf spots are reported but I’m convinced they are primarily drainage related. Insects reported to visit the plant include aphids, borers, leaf hopper, beetles, mealybugs, caterpillars and scale. We’ve never seen that as a problem.
We have found ‘Jacqueline Hillier’ very easy to multiply. Small cuttings taken late spring and summer and given mist propagation often root in just a few weeks, with or without hormone. Despite their dwarf nature, they grow fairly fast when young and a saleable one gallon container plant can be produced in less than one year. A saleable 3 gallon can be produced at the end of the second year. ‘Jacqueline Hillier” is rarely available in specimen sizes and I suspect shipping this wide statured plant will always be a problem. If cinched up tight for shipping, broken and bent branches are the norm.
Awhile back, I was wandering in the garden and I spotted a couple and their kids. From a distance I saw that they had spotted our ‘Jacqueline Hillier’ and watched them wander into the bed to get a closer look. I was a bit surprised to see the family actually “petting” the plant. That did it for me. Any plant that people want to pet has got to be worth a place in the landscape. It’s pettable.