Now is a good time to begin feeding gently with 0-10-10 (phosphorus and potassium) to strengthen root and lower trunk to provide for a good start next spring. Keep an eye out for woolly aphids, spider mites, scale and spittle bugs. They are all active at this time of year. If you find them try physical systems first (spray with hose, scrape off with hands or toothbrush, use a damp cloth) and then follow up with oil. Don’t put oil on any plant that will get the sun that day. Apply in the evening and avoid the leaves because the oil will burn them. Check the wires you applied in Spring and Summer (after defoliation). Your trees are actually beginning to put on a spurt of growth and the wires will bite really fast. Check the speed of drainage in your pots. Any bonsai that have slowly draining pots need to be repotted. Mark them with something you can find really easy so when the leaves are gone you can begin repotting without have to search around your collection.