Q. Dear Peter, I have had a Ginseng Ficus Bonsai for almost four years. Its size has increased by about a third. I have only watered it and it was doing fine until recently. Now it is beginning to drop leaves. Do I need to re-pot it into something bigger? If so, is there a certain way to do it? Please help, this is the only plant I’ve ever been able to keep alive more than a couple of months. Thank you, Georgia Riddle – Tacoma, WA
A. Ficus trees are a very useful genus for bonsai plants. Most are forgiving of severe pruning and adapt to the rigors of bonsai culture. The species you have as a bonsai is Ficus retusus. This species is very popular for “starter” bonsai because they are one of the best Ficus for bonsai culture. This tree can grow 50-60 feet tall in its native environment. Even the common Ficus benjamina, a regular in homes, office buildings and shopping malls, is used to make bonsai. Consider first if anything has changed in the environment of this bonsai. Reduced light levels can trigger leaf loss. Ficus are sensitive to change in light intensity. The plants adjust by dropping the old leaves and growing new leaves adapted to the new light levels. Changes in humidity (read decreased humidity) as well as cool temperatures (below 55 degrees F) can also trigger leaf loss. Bonsai are on such a “short leash” when it comes to water so it wouldn’t take much to trigger leaf loss. If you said you have “just watered it” does this include a liquid fertilizer? If not four years is a long time for a bonsai specimen to go without any supplemental nutrition. I would also guess that it is due for repotting since the recommendation is every 2-3 years. If you are not sure how to do this you can find some very good books on bonsai or you can visit the nearest bonsai society chapter: Olympia Bonsai Society. Meets at 7:00 PM on the second Thursday of each month at the American Legion Post #3, 3201 Boston Harbor Rd. NE, Olympia, WA. Rep: Gene Tsuji (360)491-0593. Also the Pacific Rim Bonsai Collection in Federal way also has regular lectures throughout the year (www.weyerhaeuser.com/bonsai/).