In local nurseries one can occasionally find very small cultivars of normal trees. These cultivars look like regular sized tree but are very small. After many years planted in the ground, they might be only a couple of feet high at the most. These plants come about from little buds on normal trees that do not quite get all the genetic information that they need. The growing branch is normal in every way except one. The growth is very much smaller than the rest of the tree. These growths are called witches’ brooms and can be found on a wide variety of trees and especially on conifers. Witches’ brooms can be propagated by rooting cuttings from the growth. These little trees are treasured by folks who want a very small tree for their landscaping projects.
One would think that the little trees would be a natural fit for bonsai but in fact they have had little impact on the bonsai world. One of the most important features of a fine bonsai is that the tree shows great age andone way it does this is by having a fat trunk. The little cultivars develop fat trunks only after a very, very long time.
The Kingsville boxwood is an exception and has been embraced by the bonsai world. As a result, it can be seen in many bonsai collections. The Kingsville boxwood has a long history which starts in a nursery in 1913 when it was found growing as a witches’ broom on a normal boxwood. The owner of the boxwood rooted ten cuttings of this small growth and grew them for ten years. On his death they fell into the hands of a nurseryman whose nursery was located near the town of Kingsville, Maryland, hence the name. The little boxwood was not the commercial success that the nurseryman had hoped for as a landscape plant.
Fortunately, they were discovered by the bonsai world in the 1960’s. In 1975 one of the original ten cuttings was still alive and was donated to the collection at the National Arboretum at Washington, D.C. It had been grown as nursery stock for cuttings and it took several years of training before the tree became a bonsai.
Kingsville boxwoods are now readily available and are a tree that should be in every bonsai collection. They have very small leaves that are in scale for the small trees. The little tree grows very slowly, only adding one half to three quarters of an inch each year. Because they are so slow growing the little boxwoods are generally seen as shohin bonsai or are members of a group planting. On the rare occasions when a larger Kingsville is shown, it should be appreciated as being a very old tree.
Cultural requirements of Kingsvilles are modest. Their natural growth pattern is wider that high although they can be trained as an upright tree. The trees seem to prefer somewhat deeper pots because the growth of the root ball is faster than you might expect for such a little tree whose above ground growth is painfully slow. Kingsville’s, along with regular boxwoods, do best in open shade since exposure to strong sunlight can lead to yellowing of the leaves. Kingsville’s particularly resent drying out and show their disgust at your neglect by promptly dying. As branches age they become brittle so great care in needed when working with them to avoid breakage of the branch.
Just as rarely a bud on a normal tree can get its genetic information wrong to form a witches’ broom, once in a great while buds on witches’ brooms rarely get their information right and produce a normal sized branch. When this happens, the normal branch grows so much faster than the rest of the tree that it takes charge and the smaller branches quickly die. Fortunately, Kingsville’s seem to do this less often than most of the cultivated witches’ brooms. In the rare case this does happen, the normal branch should be removed as soon as it is identified. Incidentally, as an aside, variegated plants occasionally produce a “normal” totally green leaved branch and they, too, should be removed before they take over the whole tree.
A question that frequently comes up is whether bonsai can be grown inside the house. Bonsai can and should be taken inside the house for a few days to fully enjoy them but should then be taken back outside. The problem with growing bonsai in the house is that light and humidity are difficult to manage. Extended periods in a house usually lead to a precipitous decline in health on bonsai due to poor light and dry atmosphere. Kingsville’s and tropical Ficus species are exceptions because both can be grown inside the house by careful management of light and water.
When bonsai shows and sales begin again look for Kingsville’s. They have many endearing attributes and deserve a place in your collection.