WINTER STORAGE

The usual bonsai trees are outdoor plants. They require a change of seasons and must go dormant in the winter. For this reason, non-tropical bonsai cannot be kept at room temperature during the winter. On the other hand, under certain conditions, a tree might die or lose branches when it is frozen. The main danger is having foliage that is trying to grow and is therefore losing water, while the roots are frozen and unable to supply water. This can happen in the early spring or when the weather suddenly turns from very cold to warm. In this case, the roots will still be frozen solid, but the top of the tree may warm up and transpire (lose water). So while it is all right for the roots of hardy trees to freeze, you should prevent rapid swings of temperature that can damage the tree or kill it. Be particularly careful in the early spring. Ideally, if you have a room or a cold frame you can keep between 33-40 degrees all winter, the trees can be stored there. The roots will not freeze, but the tree will still go dormant. If you do keep the trees above freezing, however, you must be careful to check them and water them more frequently.

More commonly, people use rooms that freeze, such as unheated garages or special plastic shelters (poly house). This protection from wind and weather will keep the minimum temperature slightly higher and moderate the swings in temperature. In addition, shelter prevents water loss from the foliage while the pot is frozen. This is done by keeping the light low, preventing wind and providing a moist atmosphere. In general, dormant trees in pots should be kept out of the sun and wind. Alternately, some people plant the tree, pot and all, in the ground and mulch over it. This may be combined with a poly house or other protection of the tree against wind, snow and breakage. In the spring, gradually move the trees into the sun by taking them out on moderate days (if the roots are not frozen) for a few hours; then increase the time in the sun and weather. Do not take them in the house to work on them in winter or early spring, even for a couple of hours. They may break dormancy; and then the young buds will freeze and die when you put them back outside. Once the buds begin to open, protect the tiny thin new leaves from freezing. People have found many different solutions to the winter problem. You can start making plans in the summer or fall for how you will protect your plants, then go over your plans or options with an experienced bonsaist. This is one area in which it is best to have an experienced opinion to give your trees the best chance of breaking bud in the spring.

SUMMARY

This booklet has been presented to help beginners in Pittsburgh or similar areas get a head start in bonsai. Remember, the information presented is just one way to do things, in most cases the most common or the simplest way. All of the rules, especially about styling bonsai are just the beginning. There are many variations and refinements possible after you get some hands-on experience with the basics. There are exceptions and special treatments with some plants. See our links page for information on further reading as well as sources for most of the materials and tools you might need. Bonsai is a rewarding and relaxing hobby. Have fun!