|I have a large Gardenia Tree (4 ft. tall). In the winter the Mealy bugs get very bad. We have tried soap and water, isopropyl alcohol, and various chemicals. This never seems to stop the infestation. Due to the size of the tree, it is difficult to get every leaf and nook and cranny. It is also very heavy, so taking it outside every week for repeated treatment is a chore. Not to mention heating the garage so it isn't damaged.
|Winter is a rough time for tropical plants because it's hard to provide them with the conditions they require to grow strong and be resilient against pests. Sounds like you really love this high-maintenance plant, or you'd have left it to its fate long ago. I hope my suggestions are helpful!
Have you tried dormant oil spray? It kills pests by smothering them. It is important to thoroughly cover the pests, so it may take a couple of applications to do them in. You'll find it at many garden centers and via mail order from Gardens Alive (5100 Schenely Pl., Lawrencburg, IN 47025; ph# 812/537-8560). Come spring, you should take uninfested cuttings to start new plants, and repot the tree itself in fresh, sterile soil. Feed it mild fertilizer to help it get its strength back.