All of our “outdoor trees” must remain outdoors all year. In order to stay healthy they must experience approximately 3 months of cold weather. The difference between a bonsai and a “wild” tree is the pot. The pot subjects the roots to freezing temperatures. A wild trees roots are protected from the elements by the soil.
Here are the first steps to preparing your tree for dormancy:
1. Remove all leaves and debris from the pots surface.
2. Apply soil to cover any exposed roots.
3. Remove any algae, insect cocoons, cobwebs and mosses.
The next step is to protect your tree from the elements:
1. Place your tree on the ground. This helps by reducing dramatic temperature fluctuations. You may choose to put your pot in some Styrofoam or bury your pot in some mulch. If burying in the mulch, choose a location that will not stay wet.
2. Protect your tree from the wind and sun. The wind removes water from the foliage in a process called desiccation. You also want to avoid a large amount of sun exposure during periods of warmer weather during winter. If the foliage of the tree sees higher temperatures it will think spring, and if the roots are still frozen this will severely stress your tree. You can do this in several ways:
a. Group your trees together, like penguins in the Antarctic. Start with your most delicate trees in the middle, such as the deciduous trees. Surround them with Junipers and finally your pines.
b. Build a wall to protect them.
c. Place them in a cold house. An unheated garage with a window or an out porch will work just as well.
No matter where you place your tree you will still need to check it occasionally for water. The number one reason trees die in the winter is due to lack of water. The tree may be dormant but the roots are still growing. This is especially important if your tree is in a garage or cold house. If your trees are outside you can carefully pack them in snow. The snow protects them from the wind, freezing temperatures, and waters them in the process.
“What good is the warmth of summer, without the cold of winter to give it sweetness.” John Steinbeck