Hibiscus tend to drop a lot of yellowing leaves just before a flush of growth.
Seems the right time for this to happen.
Maybe the fertilizing has hastened this.
Probably not a problem.
It might be a good time to trim them if needed.
Overwatering also causes a lot of leaf drop.
But it does sound like a normal growth situation to me.
Hope it all straightens out really soon.

Thanks, I guess it kinda freaked me out that they were all doing it at the same time. Seems to have slacked off now. I do think they need to be sprayed for bugs again, though.

A couple of mine have just dropped lots of leaves too. I think it's pretty normal this time of year. I wouldn't worry unless you don't see any new leaves appearing!

Kate

The ones I just purchased for the backyard did the same thing...and they are blooming beautifully...new growth as well.

Kim