I have Hibiscus plants that I found what looked like egg's on the flower buds and some black leaves?

Are you sure they're not aphids? Aphids look like tiny greenish-blue eggs but, on closer inspection, you'll see their little legs. And aphids are especially fond of hibiscus buds.



The best way to get rid of them is to use a high-pressure spray from a hose nozzle to knock them off the plant. Get both sides of the leaves, too. Then either apply a general insecticide, or spray a mixture of dish washing liquid in water all over the plant. I have also had minimal success with ladybugs (ladybugs eat aphids) - the problem is that they just fly away without eating all the aphids. It's also kind of a slow process.



As far as the black spots, this may be cold damage. Hibiscus is a tropical plant and can get damaged by temperatures less than around 40 degrees. They also will not produce flowers until the temperature is above 55 degrees consistently. Until then, expect bud and leaf drop for no apparent reason.
I have Hibiscus plants that I found what looked like egg's on the flower buds and some black leaves?
do you have tropical or hardy hibiscus? the hardy one are commomly know as rose of sharon, and flowers last only one day. i have a bunch of these. i get the same things on mine, and then, later in the summer thousands of tiny red and black bugs. they dont seem to bother anything, just sit there and are gone when it cools down in the fall.
Reply:Surely sounds like aphids.



The black areas on the leaves is mold growing on the honeydew secretion from the aphids.



Spray with detergent solution - you will be able to rub off the black stuff.