Wheel of Fortune

Behind a privacy row of Carpinus betulus ‘Fastigiata’ (Columnar European Hornbeams), situated in front of a large curvaceous bed of Imperata cylindrica ‘Red Baron’ (Japanese Blood Grass) and flanked by two Acer palmatum ‘Sharp’s Pygmy’ (Sharp’s Pygmy dwarf Japanese maples) lays a most curious tree on our property. Colleagues in the field have long been stumped identifying this small ornamental tree. Customers in our garden center have taken a stab at what it is by labeling it as a ficus tree, a type of rhododendron, some sort of mountain laurel or a type of euonymus. The truth of the matter, it is properly identified as Trochodendron aralioides (Wheel-tree).
Derived from the Greek words trochos meaning wheel and dendron meaning tree, the common name refers to the stamens (about 40-70 in total) appearing like spokes on a wheel comprising what is to be the flower. The full image of the flower, to me, looks like tiny green pin cushions held tightly together, suspended over dark green, leathery foliage, depicting an almost sci-fi flower presentation. The flower color is a light green smartly contrasting monochromatically with, again, darker green, leathery foliage. One can expect these unique flowers to appear late April through May. The leaves are three to five inches long, somewhat oval or lanceolate, leathery, lustrous and shallowly toothed or serrated. What is most surprising to many is that this tree may look “tropicalsih” in appearance, but, in fact, it is a true broadleaf evergreen tree that is unmistakingly “hardy!” I say unmistakingly hardy because academically this tree has been listed as a borderline zone 7 plant. In fact, we have been selling Trochodendron for several years now, in a zone 6 climate, and had fantastic results. Another misnomer is that the growing conditions for Wheel-tree need to be moist, well drained soil with shade being the preferred location. While I agree that this can be an ideal situation, ours is growing quite well on this west side of our house, on the front lawn, without any obstruction. Not to mention that in the winter months this particular area of our lawn can be quite wet. I do agree with popular belief that attempts to protect this tree from winter sun and desiccating winds is advantageous. Ours stood within a burlap barricade for the first winter and has since been on its own. Also noteworthy, once they’re in the ground they don’t like to be moved around. So plan for the future! The overall outline of this tenacious tree is roughly ten to fifteen feet high and about half as wide. Other attributes include reddish-bronze new growth, bronze green fall color and bark which is reminiscent of some conifers.
Technical stuff: anyone who has read a “Dummies Book” i.e. Computers for Dummies, Wine for Dummies, Golf for Dummies etc. will appreciate that reference. Considered a primitive feature of the Wheel-tree is the lack of vessels in its vascular system. Specialized xylem cells called tracheids (elongated cells) carry food and water through the plant. Very few flowering plants share this trait. However, is this primitive or advancement over time? Do they really need those vessels to survive or have Wheel-trees become more productive with fewer parts? A debate for the academics to discuss.
Native to the mountain forests of Japan, southern Korea and Taiwan, Trochodendron aralioides is the sole species to the genus Trochodendron and popularly considered the sole species in the family Trochodendraceae. Although, some botanists put the genus Tetracentron in the same family. Typically described as having a shrubby appearance, ours has become a handsome layered tree with very little effort. An attribute I am most enamored with is its lime-green outer branches. A nice contrast to the dark green foliage and light-green flowers when they appear.
Avowedly, not every garden will be fortunate enough to showcase such a prized ornamental. Difficult to find and even more difficult to secure, availability and demand for Trochodendron are growing. A gorgeous, evergreen tree to sit among larger deciduous trees and admire as a specimen! Wheel-tree, a flowering evergreen tree, providing year round interest will have you and your friends talking and others wishing they were as fortunate.