Will fluorescent lights be enough light for wintering hibiscus?
The plant requires bright light, which in your zone (even in winter), should not be an issue, though sunlight in winter is less intense. You can, however, try supplementing the light with a fluorescent bulb placed 1-2 feet away from the plant. This should be enough. Worse case scenario, your hibiscus will go dormant without enough light but will "wake" up with the return of spring.