Jennifer Schultz Nelson
Extension Educator, Horticulture
I was fascinated by bonsai the first time I saw some for sale at a local nursery in high school. They were as cute as could be—perfect trees in miniature. I surrendered $15 of my hard earned babysitting money and took home a little boxwood bonsai. It lived through the summer, and my efforts to overwinter it properly failed miserably. In hindsight, perhaps a mass-produced bonsai purchased at the local big box store was not really a quality bonsai. But it was a good place to start.
Bonsai (pronounced bone-sigh) is an ancient art of cultivating woody or semi-woody plants in miniature. "Bon" means tray, and "sai" means growing or planting. So bonsai may be translated as "tray growing" or "tray planting".
The Chinese are credited with developing the art of growing plants in miniature, which they termed "penzai". The Japanese adopted this practice and renamed it bonsai.
People sometimes incorrectly assume that plants grown as bonsai are special varieties that are naturally small. On the contrary, bonsai are trees and plants that would grow many times larger if they were not trained as bonsai. A strict regimen of root and top pruning keeps the trees small.
How are bonsai grown? There are three sources of bonsai material: seed, collected material, or nursery stock. Each has its advantages.
A fact easily overlooked is that the bonsai we see in on display or for sale have attained a level of maturity as a bonsai. Often plants are grown for months to years in training before they are ever displayed as bonsai.
Growing bonsai from seed is a long, painstaking process. It will take at least several years before a seedling is big enough to begin any rigorous bonsai training. This process is only for very patient people.
Collecting plant material from the outdoors has its advantages. Ideally, the plant may have been naturally stunted by wind and the elements, but more often the attraction is a good trunk and branch structure that will make a good bonsai with training. Unfortunately, digging up plants is frowned upon in most wild areas unless you are the property owner. Also, transplanting an established tree into a pot may cause enough stress to kill the tree.
Using nursery material for bonsai is very popular. A tree or shrub with a nicely shaped trunk and branches can be pruned and immediately trained as a bonsai. Since it is already in a pot, there is less stress on the plant.
Bonsai training involves pruning both the roots and the branches. Restricting the root system by pruning helps to restrict the top growth. A small root system transports less water and nutrients than a large root system. Since the amount of water reaching the top parts of the plant is restricted, growth is reduced. This reduced growth rate helps keep the tree small.
Pruning the top growth keeps it in balance with the restricted root system. If the top growth is allowed to get too much out of balance with the roots, the roots will not be able to keep up and the plant will be stressed and likely lose leaves and have branch die back.
The top growth of plants is manipulated by pruning and wiring to achieve the desired bonsai shape. There are several categories of bonsai shape, all relating to trunk and branch placement. Some plants lend themselves to one shape or another based on their natural growth habit. If wire is used to shape branches, it is not left on indefinitely. It must be removed before the plant grows too much, or the wire will leave undesirable marks on the bark.
Bonsai are by nature high maintenance plants. Since they are grown in small pots that are relatively shallow, their water needs are high. It is not unusual to need to water bonsai twice a day or more in hot weather.
Many of the trees traditionally grown as bonsai need a dormant period outdoors to thrive. Just like trees in our landscape, deciduous bonsai develop fall color and lose their leaves in the fall. Evergreen plants go dormant. Unlike our landscape trees though, these trees need to be protected for the winter either in a cold frame or with their pots buried to protect their roots from freezing.
It is also possible to use tropical houseplants as material for bonsai. This avoids the overwintering issue altogether.
Ficus and jade plants make great bonsai. They are easy to find, easy to propagate, and inexpensive. For most gardeners, the process of shaping a bonsai is as important if not more important than the finished product, so why not use plant material that you can afford to experiment with?
The subject of bonsai is a fascinating merger of art and science. There is no shortage of books and articles available on the subject. If you would like to learn more about bonsai, join us at the Macon County Extension office at 1 p.m. on Tuesday October 13 or 7 p.m. on Thursday October 15 for a telenet presentation by University of Illinois Extension Specialist Phil Nixon. Cost is $5 and includes color handouts and light refreshments. Call 877-6042 or go to www.extension.uiuc.edu/macon to register.