I have two hibiscus trees [potted] that did really well last summer. I brought them in over the winter, cut them back, and they both had great new growth of full green leaves. When it got warmer here [I'm in Vancouver, BC] I took them outside. Since then, they first turned pale yellow and something like the texture of damp tissue paper, and then the leaves all but fell off. One tree still has some green leaves, the other is pretty much bare. I have no idea what's happened to them, or what to do to get them back. Any ideas?
Tropical hibiscus do not like to be moved and they don't like to go below 10°C either. (Which has been happening in Vancouver.) Leaf drop often occurs when they are moved in or out of doors. Just keep it in a good spot with even watering and it will probably recover. It will take it a while to adjust. It's not really warm enough for it outdoors here.
Probably best to just leave it. Weather is getting warmer. Just leave it where it gets plenty of sun and give it regular water. Don't fertilize until it starts to grow again. Do look close for pests as well as that is always a possibility, though more of a problem when you are bringing plants indoors.
I planted my Hibiscus about four months ago, it was infested with ants, had brown spots. The easiest to get rid of was the spots, I used Physan 20. The ants were tough, I used combat ant gel. That took a couple of months. Now my only problem is yellow leaves, including small new ones. I planted in organic potting mix, I use organic fertilizer, it bloom like crazy, but the constant yellow leaves are a puzzle. I am going to try the suggestion of Epsom salts. I live in southern CA, and Hibiscus does well here.
