Winterizing Hibiscus against aphids
I have a tropical hibiscus that is now 10 years old. She stays inside during the cold months and I prune her back hard before setting the plant outside for the summer months.
Over the past 4 years, in a new house, I have seen that the plant becomes infested with aphids. I usually bring the plant indoors in October, and the plant looks healthy, with no obvious signs of aphids, however by February, the aphids have overtaken the plant, with leaves yellowing and buds covered by aphids.
When I bring the plant indoors, I do prune it back again, and fertilize regulary with a rose and flower product that also is supposed to kills insects. Insecticidal soaps and other aphid control agents have not worked, but I admit that I have not begun using them until the problem is apparent.
Any suggestions in terms of what I should do before bringing the plant indoors this fall and how to prevent this infestation from recurring? Overall, the plant is healthy and blooms prolifically outdoors and then indoors from November through January, but by February, the aphids do their number on the plant.