|We planted our Chinese hibiscus outside last October. It seemed to be doing well, blooming, etc., but then the leaves started developing black spots and turned yellow, hten dropped off. The people at the nursery recommended that we acidified the soil, which we did. Now that spring has arrived, however, the hibiscus doesn't appear to be doing much better. It has lost perhaps 70 percent of its leaves and no new leaves seem to be coming out. What is the problem? There is no frost in our area, the Hibiscus is planted against a south-facing wall that can be breezy at times. Will it die?|
|Yellowing leaves can be a symptom of many problems including overwatering, underwatering, salt burn, lack of nitrogen, iron chlorosis, fertilizer burn, and transplant shock. Black spots can indicate a disease, but it's difficult for me to diagnose the problem without seeing it first hand. I'd prune the plant back to remove the damaged stems and leaves and encourage healthy new growth.
All Hibiscus require full sun, good drainage, regular, deep watering and frequent feeding. If you prune the plant in early spring, you'll encourage new flowering stems. If you pinch out the tips of the new growth in the late spring and early summer, flower production will increase. When you water, apply liberally to wet the entire root system. Feed plants every two weeks with a diluted liquid fertilizer (from spring through the end of summer), pinch out the the tips of the new stems and your plant should produce blooms.