There is a 5 ft althea (in tree form) in my garden which looks quite healthy,has lush foliage, gets fertilized and watered regularly and is exposed to partial sun. Every year it develops a large quantity of bloom buds; when they reach maturity they never open and actually bloom; just stay tightly closed with a tiny light green rim around the top edge. When I open one of them up there appears to be a blossom inside - it just never comes out. What am I doing wrong? I'd appreciate some advice. Thanks!
I agree, it needs lots of sun, regular water and very little in the way of fertilizer, just a good feed in the spring. Sounds like all its' energy is going into growth and bud formation. Even sorely neglected ones will bloom fairly well once established.
You might also investigate whether the problem is due to thrips--they can cause this in tropical Hibiscus, and since ROS is also a species of Hibiscus maybe they are susceptible as well. In the tropicals thrips will often cause the buds to drop off as well as not open so I'm not sure it matches your symptoms, but probably worth checking.
Re: Rose of Sharon Blooms To:flowAjen, themoonhowl, ecrane3, Beach_Barbie
Thank you all so much for responding - you verified what I sort of suspected - I was doing the killing with kindness bit (have a tendency to do that), especially since there is an althea in the back woods that's pretty much neglected - and it BLOOMS! Will quit fertilizing and will check it for thrips just in case. Thanks again! Happy digging.