The term bonsai ("tree in a tray") is used to describe trees and shrubs trained in miniature forms and grown in special containers.
A bonsai is dwarfed by training that involves pruning, wiring, watering, repotting and fertilizing. The container you grow them in should be "frost proof" and have drainage holes.
If you purchase a bonsai, look at the overall shape of the plant. Take a photograph or draw a picture of how the tree or shrub looks now and then decide how you would like it to look in the future. There are both informal and formal styles. As you examine your plant, its natural shape may help you decide on a style. Trees with straight trunks work well for formal bonsai while those with trunks that are spreading may form a natural cascade — a more informal style.
Good trees and shrubs for beginners
The following are outdoor (temperate climate) plants – plants that are adaptable to a range of environments:
beech -- Fagus species
box -- Buxus species
Chinese elm -- Ulmus parvifolia
crabapple varieties -- Malus species and cultivars
ginkgo -- Ginkgo biloba
juniper -- Juniperus chinensis var. procumbens 'Nana' and other selections
larch species -- Larix species
maples, including Japanese maples -- Acer palmatum -- and Trident maples -- Acer buergerianum
pines -- Pinus sylvestris and other species
spruces -- Picea species.
Don't make the mistake of growing your bonsai as an indoor plant. They do best (unless they are tropical plants) when grown outdoors year-round. Like their full-size cousins growing in your backyard, temperate climate bonsai need to experience the four seasons (go through dormancy, set flower buds, etc). Make sure they receive plenty of light, but protect them from drying winds and provide some shade during hot months for shade-loving types.
In Zone 6 or regions with colder climates, starting in November or December and through the winter, you can keep your bonsai in a cold frame or in a cool, unheated greenhouse, garage, or unheated sun porch.
Although they need to experience four seasons, it is best to keep the plants from freezing and thawing. Be sure to vent cold frames on hot, sunny days. March 1, or once temperatures get above 40 degrees F, is a good time to bring them back outside.
Water when the top of the soil is dry to the touch. Often this will be on a daily basis. Adjust according to the season. For example, in the winter check plants in cold frames every few weeks. Use a watering can with an attachment that breaks up the water or a hose with a rain-like spray.
Bonsai fertilizing guidelines
- As a rule, fertilize only during the active growing months.
- For vegetative growth use fertilizers with a high nitrogen analysis. (N)
- For flowers and fruit use a fertilizer with more phosphorous (P) and potassium (K) than nitrogen.
- Deciduous trees like maples and elms need more feeding than coniferous types (such as pines and spruces).
Younger trees in the beginning stages of training need repotting more frequently (every 1-2 years) than mature trees which can be left in the same container for six years or more. In general deciduous trees need repotting more often than conifers which only need to be repotted every 3 to 5 years.
The best time to prune foliage plants is when they are actively growing. Take time to find out if flowering plants bloom on new or old wood. This will help you determine the best time to prune and not remove potential flowers or fruit. Roots should be pruned when plants are repotted.
For more info on bonsai visit The American Bonsai Society.