American Bonsai Society

Chorisia speciosa

The Silk Floss Tree

By Lew Buller

In San Diego, the Chorisia speciosa (floss silk tree) starts blooming in early fall and continues to carry flowers until late December, offering color at an otherwise drab time of year. The tree is used as a street tree in San Diego, and its flowers are one of the main reasons. Its hardiness, its unusual green bark and thorny trunk, its rapid growth–3 to 5 feet a year for the first few years; 30 to 60 feet at maturity–and its tolerance for dry, hot weather make this Brazilian native a good choice for landscapes here.

After the floss silk tree flowers, it produces large balls of cottony kapok, and when kapok is shed, it looks like snow beneath the tree. It is a member of the kapok family of flowering trees and shrubs but its kapok is not so good as that from the kapok tree itself. Older readers may remember that during World War II, kapok was used in life preservers, now it is used as stuffing in pillows, as insulation, and as a substitute for absorbent cotton in surgery.

American Bonsai Society

Zelkova

By Randy Davis

It’s mid July and the bonsai activities have dwindled for the most part to summer pinching and pad-development work. This is the time of year that the observant bonsai enthusiast is paying attention to, among other things, a plant’s ability to reduce the size of its leaves under bonsai cultural practices.  Some plants are better at producing small leaves than others and, with the smaller size bonsai becoming more popular these days, plants with naturally small leaves or genera that will respond to pruning and pinching with small leaves should gain your attention. For those of you who love bonsai under 12 inches, a good candidate is the Zelkova. We have discussed the world of Elms and Zelkova is closely related.  As a bonsai subject, Zelkova has been used for many years in Asia and is often seen more in Europe than it is here in the United States. There are a number of species of Zelkova one of which (Z. sicula) has recently been found on the Italian island of Sicily which are shrub-like and classified as a rare and endangered species. The most commonly used Zelkova for bonsai is the Japanese graybark elm (Z. serrata) which has been used extensively in Japan. It has too often been relegated to small broom-style bonsai because of its excellent branch ramification and leaf reduction characteristics. A species that is also worth looking at is the Chinese Zelkova (Z. sinica) which may be treated the same as Japanese Zelkova. In fact, it is very difficult to tell the difference between them.  Another species from Western Europe (Z. carpinifolia) is also used but not often seen.  I have had a few of each of these species here at the nursery for a number of years and they are finally getting to the size that they can be worked on as young specimens.