WATERING – The need for water will continue to diminish this month since the weather will be cooler. Therefore, water only as needed in order to prevent root rot. If you need to water your plants, try to water them early in the day. If the temperature drops to freezing or below, the water soaked bonsai soil could possibly expand and break the container.
FEEDING – Because of shorter days and cooler temperatures, plants will be doing little to no growing. You will probably not even have to fertilize your plants at this time of the year. If you feel you still need to fertilize, remember to use a fertilizer with no nitrogen in it.
WIRING – Wiring or removing wire from a deciduous tree is a much easier job when there are no leaves to get in the way and the structure of the tree can be seen more easily. Therefore, if all the leaves on your deciduous trees have fallen off, remove and replace the wire as necessary. Continue to keep a close eye on the wire on your other trees as well because the branches will continue to thicken. Leaving the wire on the plant for too long will disfigure the branches; therefore, remove the wire if the branch remains in the desired position or if the wire is cutting into the cambium.
PESTS AND DISEASES – With the colder temperatures, the activity of harmful insects will slow down or become non-existent. If it gets cold enough, the cold temperatures will actually kill insects, however continue to check for pests and diseases and treat accordingly with soaps and oils if needed. Always remember to spray a small branch first in order to make sure there will be no phytotoxic* reaction to the plant from the soap and oil spray. An example of a plant that will drop all of its leaves if sprayed with soaps and oils is Fukien Tea. *Phytotoxicity is an adverse response in plants due to chemicals applied to the leaves or soil.
TRIMMING – Deciduous trees such as maples, crepe myrtles, cypress and elms should have lost their leaves by now. They need a complete rest during the winter months. If not, they will become weaker expending too much energy maintaining older leaves that should have already fallen off. Therefore, remove all the remaining foliage on deciduous trees. Continue to trim other evergreen plants as necessary to maintain the desired shape, but this should become almost non-existent because of the lower levels of nitrogen, shorter days, and cold temperatures.
PRUNING – Avoid heavy pruning if possible. Pruning will cause excessive, tender new growth, which will get damaged in cold weather. Even the new growth on cold hardy plants such as hollies and boxwoods would be damaged. It would be a waste of energy for the plant to lose all the new growth.
LIGHT – Plants that have been protected from the harsh summer sun such as maples and azalea plants can now be exposed to more sunlight. Rotating the trees on a weekly basis will prevent the trees from becoming one sided.
TEMPERATURES – The colder temperatures will continue this month but it will probably fluctuate from mild to cold so be prepared to protect you tropical plants. Place all of your tropical plants on one bench so you will not forget any. Also, if you have to move your plants back and forth from a protected location back outside, you may want to leave them on a cart or a tray so it is an easier chore. Some examples of tropical plants are ficus, buttonwood, bougainvillea, and Fukien Tea. Please refer to the chart in November’s newsletter as to when to take in your tropical plants.
REPOTTING – The beginning of January is a good time to prepare for repotting by making batches of soil and cleaning unused, dirty pots ahead of time. This will make the task of repotting go much faster and more enjoyable. When cleaning pots, use a water and bleach solution to disinfect pots and let them air dry. Also, do not to forget to cut up small pieces of screen to cover the drain holes. Depending on how many plants are in your collection, repotting can begin towards the end of January. Begin repotting your evergreen material such as hollies, boxwoods, junipers, and azaleas. It is recommended to repot deciduous plants when the growing buds begin to swell which is usually sometime in February. But if you are like me and have many deciduous plants, you may want to begin to repot deciduous plants at the end of January, but make sure all the older leaves have fallen off or have been removed. Avoid repotting all tropical plants.
COLLECTING MATERIAL – Keep your eyes open for any landscape plants that may be good bonsai material. About a month or two before actually digging it out of the ground, cut a circle around the plant by using a shovel to encourage more fibrous roots closer to the trunk. Wait until the end of January or February before actually digging it out of the ground in order to make sure the material is dormant.