As is true with all traditionally-sized trees, bonsai trees can undergo dramatic changes in their appearance with the changing of the seasons. The type of care that you give your bonsai will also need to be adjusted as the seasons change and the needs of your bonsai plants and trees change.

Spring Care

After a period of winter sleep, springtime is when you begin to see evidence of new growth in your bonsai plant and trees. Bonsai gardeners know that this is the busiest time of the year as there is much work to be done on their awakening plants.

Most deciduous trees, like the Chinese elm bonsai for example, will need to be repotted and have their roots pruned at this time of year if they weren't already repotted during the late winter (the optimal time). It's essential to do any repotting of bonsai before the first buds break.

Spring is also the best time for pruning any dead branches before they are concealed by foliage. Springtime is when new shoots will appear and you need to be sure to cut them back.

If you are training coniferous trees, spring is the time to apply the wires, or get rid of any wires that may appear to be cutting into the tree's bark.

If you are planning on fertilizing your bonsai trees in the spring be sure that you only use a diluted mixture on any plants that you have recently pruned it's roots and repotted because a full strength fertilizer may burn the plant's roots.

Summer Care

Your outdoor plants are going to experience their maximum rate of growth during the long sunny days of summer. Root pruning and re-potting at this time of year will cause great harm to your bonsai plants so make sure to get it all done in late winter or early spring. It won't do any harm to your bonsai plants and trees if you continue to trim back new shoots, prune, and pinch buds back all summer long. The shoots of deciduous trees should be cut back to one or two pairs of leaves, and the buds on conifers should be carefully plucked as they begin to enlargen.

Summer is a good time to train your deciduous trees using the wiring techniques. Remove any wires that you may have applied during the previous summer to make sure that it doesn't cut into the tree's bark and cause damage.

Monitor the soil of your potted bonsai regularly, making sure to never allow the soil to dry out completely. You may find that it is necessary to water your bonsai plants more than once a day if the weather is extremely hot.

Summer is also the time to feed your trees with fertilizer. Fertilizing should continue throughout the summer and then into mid- fall

Fall Care

When the number of hours of sunlight per day begins to get fewer and fewer, which signals the change of season to fall, the growth rate of your bonsai trees will slow down. This is the time of year when most deciduous trees, including small bonsai trees, begin to exhibit their beautifully colored fall leaves.

It's OK to prune juniper and pine trees in the fall, but when you prune deciduous trees it will cause the tree to burst with new growth. This should be avoided because the new growth uses precious food supplies that the tree will need during winter.

Training wire that you might have applied during spring and summer should be removed in the fall if the branches and trunk have set into their desired positions.

Your deciduous trees will require much less water after they have dropped their leaves in preparation for winter. They'll only need a little bit of water when the soil feels dry. Conifers, on the other hand, will continue to need water, but at a lesser amount than during hot summer months.

It is recommended that you harden off the current years growth by applying 1-2 applications of nitrogen-free fertilizer to your bonsai plant beginning around mid-autumn.

Winter Care

Deciduous bonsai trees don't require much care during winter while they are in a inactive stage, but as mentioned in the prior paragraph you still need to water your conifers.

This is not the time to prune or wire, but it is an excellent time to quietly contemplate your trees, get to know them better, and to visualize the resulting masterpiece that you will once again be able to work with come springtime.