Tropical hibiscus: how cold is too cold?
I have a growing number of tropical hibiscus plants that I will be bringing inside for the winter. How cold tolerant are they? I will watch for frost warnings, of course, but is there a temperature in the low 40Âs (or wherever) to which they should not be exposed? A cut-off point? They are blooming a lot and I hate to suddenly reduce the light they are getting while blooming.