Winter care for bonsai - In the event of a hard freeze in your area, frost-tender bonsai such as bougainvillea, elephant's food, the various Ficus, lantana, natal plum, and so forth need extra protection. If you can, before sunset move the trees close to the house and under a porch or the edge of the roof so that vertical air drafts will not directly reach them.Elevate the pots on concrete blocks or a table or bench and put a section of newspaper directly under each pot to provide a layer of insulation. If winds or breezes are likely, drape a newspaper page over each pot, anchoring it under the corners of the pot. Do not use plastic sheeting.
An unheated but protected room, garage, or storage closet can also be used. Again, place an insulative layer of newspaper below the pots.
If you notice or suspect frost damage to your bonsai, it is best to wait until the appearance of new growth before trimming any branches. Plants will always surprise you with their hardiness.
Be sure to keep an eye on the water needs of each tree. Watering can generally be done less frequently now. But do pay attention to the dew point: a few days in the winter here can have very, very low dewpoints. At those times moisture is easily lost from even leafless trees.
DO NOT fertilize in the winter. Wait until the appearance of swelling leaf buds before feeding any tree.
Take time now to clean and oil your tools, clean your empty pots, review your books and magazines.
