The leaves on my Double Red Althea are turning yellow and falling off. I have not been overwatering it. I did not water for several days until its leaves were starting to droop. I then watered sparingly. Any ideas? Thanks.
Double red althea
How long has the plant been in the ground? Hibiscus, especially newly planted one, tend to overreact to drying out too much and Rose-of-Sharon (H. syriacus) is no different. Most likely it got a little too dry and the rocks-as-mulch amplified the effect by heating them up and cooking the roots a little. The leaves that are currently yellow will probably still fall off but it shouldn't get any worse.
This was planted 12 days ago. I have since upped the watering and it looks better. The yellowing leaves are drying out and falling off. Thanks