Hi Jan,
Good question. I bet a lot of people have a similar situation.
Growing hibiscus inside the house is done for 2 reasons - first would be to guarantee the survival of the tropical hibiscus over winter and second would be to enjoy growing them in winter and getting growth and blooms. Survival is important, of course, and in some situations that is the best that can be expected. However, if it is possible to both keep them alive and get them to grow and bloom then of course we want to do that.
Growing indoors is all about heat and light. If the plants can be placed in rooms that are warmed up daily and kept in the 60's at night they will do best. Cooler rooms are a lot better than outdoors but won't encourage growth and blooming as well as warmer locations. Warmth is #1, but light is a close second. The winter sun is lower in the sky than in summer, and sometimes shines directly into windows in winter that do not get direct sun in summer. If you can identify the sunniest windows in your home, and then place the hibiscus where they will get some of this direct sun they will be most likely to grow and bloom during winter.
We have one member of this forum who is successfully growing his hibiscus in a room with no windows and no sunlight. To do that a powerful 1000 Watt HID light was installed, and it has provided enough light to get lots of lush growth and the plants, which were pruned in late Fall, are now budding up.
If your plants are in a warm location that gets good light but they still lose their lower leaves and do not seem happy then suspect spider mites in that case. The obnoxious little pests like the indoor environment and are protected from most predator insects that feed on them outside in the garden. It could be that they did their damage and are now gone but unless a very close inspection with proper magnifier shows no more mites it is best to assume that some are still on the plants and are damaging the leaves.
We have many reports of dealing with spider mites in other areas of this forum. Use the Search function at the top right above - type spider mites in the blank field and then press the "Search" button. There is also a detailed spider mite page on the HVH main website under "Pests" at this link:
http://www.hiddenvalleyhibiscus.com/care/spidermites.htmOnce the spider mites are under control, and the plants are in the warmest, brightest conditions in the house, how can the bare stem plants be encouraged to leaf out again? In addition to regular applications of fertilizer, Growth Enhancer can be used. The hormones in this product naturally and gently encourage new growth. The stronger hormones in Wake-up Spray can also help, although it works best as a spray when some leaves are present to absorb it.
The most certain way to get new growth on bare stems is to prune those stems half to 2/3s of the way down the stem. However, since the plants are not actively growing it is safest to prune only one stem on each plant. Wait for new growth to show on the pruned stem and then prune a second stem. By doing it just one stem at a time the plant will always have leaves to generate energy while the pruned stem starts new growth. For more details on pruning see the pruning section of the main website.
Good luck with your indoor plants and please let us know what your future experience is!
Charlie
