Hello, I grew a baobab (adansonia dig.) from seed, started in 2003. The tree is now about 6 feet tall and every fall and winter has gone dormant. This year it has not lost its leaves yet, and none show signs of yellowing to fall off. Previously, I have always placed it outside in the sun during the summer, and usually in August it starts to look unwell, and by October the leaves are gone or almost gone. I had it outside again this summer and it was quite hot (regularly 95+ with heat indexes of over 100), and it grew almost 2 feet! I repotted it again this past spring into a bigger pot of cactus/tropical soil mix. Do these trees only sometimes go dormant? Or is it maybe because we had such hot temperatures, then it cooled suddenly so I brought it inside (so it never experienced gradually cooler temperatures)? It isn't growing as fast as it was but still has new growth on it. Should I still expect it to go dormant eventually? Will this impact its growth next spring, does it require a certain amount of time to be dormant?
Sometimes, tropical and semi-tropical plants will go through a period of "quiescence" where growth significantly slows, but the plant does not go through a true dormant period. The old foliage may drop in the Spring as new growth is beginning. The other scenario is that because you interrupted the dormancy "triggers" by bringing the plant indoors, it may not this year, but will likely the next...however, if the plant flowers/fruits, it may not if it hasn't had it's rest. When temperatures begin to drop and the daylight hours shorten outdoors, growth of the plant slows and will typically trigger dormancy. However, those of us that bring the plants indoors may interrupt the process with the warmer indoor temperatures. It is just my theory, as I have experienced this to varying degrees with some of my plants. My Adeniums and Delonix decaryi have not begun their dormancy yet, either....any day now...waiting. Restrict the water a bit more and move the plant to a more interior spot that has less light. If you have a cooler basement that gets sufficient light, this may work, as well. http://www.bihrmann.com/caudiciforms/div/dorm.asp This source claims that some plants do not need a true dormant period, but are rather forced into it by conditions in nature. Mark
Ok, that makes sense. The one other thing I usually noticed right before it went dormant is it would get an increasing infestation of maybe spider mites? Tiny little specks that would mostly be on the underside of the leaves, make tiny webs, and the leaves would be more of a speckled color. These also don't seem to be present this year. I would try everything to get rid of them in past years, from using soap-based insecticide, the pest killers you mix with water that the plant takes up and it is supposed to kill pests that eat any part of the plant, and my final try was wiping down the leaves with watered down rubbing alcohol. If I had all the time in the world, the alcohol worked best. I watered it down enough to not hurt the plant but the "bugs" would stay gone a while. It just needed to be done quite a few times a week to make a difference. Is it normal to get infestations like this as the tree goes dormant?
http://www.ohioagriculture.gov/plnt/STUDY_MATERIAL/6B Interior plantscape 2007.pdf I found this recently. This is probably the best information I have found on plant diseases and pests, and I have bookmarked it on my computer. Spider mite information is on pages 57-58. Any infestation of pests appears to be independent of dormancy or dormancy triggers. You said that you repotted the plant this past year, and this year you did not have an infestation of spider mites...no coincidence. The soil you were using before was likely contaminated.
