I have recently planted Pere Hibi Luna Pink Swirl in my yard. Two plants are near the foundation of my front cement porch, the third in a separate bed away from the house. The two plants have many buds on them, but they have begun turning black and I suspect will not bloom. What could be causing this and how can it be corrected? Is there a soil pH that I should be watching out for? (Previously in this same bed I had black eyed Susans. They grew well but always the leaves had black spots on them. ) I am watering them daily and have fed them each week since planting them three weeks ago.
They are likely bugs. Many of the smaller bugs attach to the plant and move very little. Treat the plant with neem oil and that should take care of them.
My Dwarf Luna Hibiscus plants were gorgeous until about a month ago. I admit I planted them about 6" too close together 4 years ago. And they have multiplied - making a neighborhood statement when flowering (lots of compliments and people asking for seeds). The spotted leaves sometimes go fully yellow (then brown) - down the center/middle of leaf first. Then entire leaf does. I have tried a couple fungicides, but one was a preventative 3-in-1. The other Propiconazole. No impact. Hoeever, I could not spray all the leaves because these were VERY dense bushes. (No access to interior or back leaves easily). The leaves spread on ground Photo is from the beginning of the problem. The damaged leaves were closest to the soil. Now, the pictures show spots all over the plants - worse on the plants on left half of garden - which are close up in photo.
The dense planting and lack of airflow has likely led to fungal issues.
Though you many be able to control some of the issue, without improvement in growing conditions you may have trouble reversing the issue.