I have a beautiful astilbe, the foliage is great. It has numerous buds all over it and they are not opening! This same thing happened last year, they never did open!! What is wrong with this silly plant? How can it be so nice and bushy with beautiful foliage and all the buds and NEVER open????????!!
Astilbe blooms don't open!
They thrive in shady, moist areas!! If you are growing it under other conditions it may be keeping it's eyes closed to keep out the sun....lol!! Sorry joke!! But seriously, it could have something to do with the growing conditions.
Sounds like it might have thrips or spider mites causing the buds not to open. Hold a clean white sheet of paper under the buds and flick them with your fingers. You should be able to see any little critters crawling around on the paper.
After reading your post, I went out and slapped around my variegated ROS. =P I saw just a couple of yellowish tiny spider-like guys. ? This is the second year I've had it.. full of buds AGAIN and no blooms. Got a tiny bit of browning on some leaves. I've fed it mildly and it gets plently of sun.The buds are kinda hard and waxy like. ( not mushy )I have another non-variegated ROS blooming it's head off in the back. Kinda depressing. I'll watch this post for sure.
I asked someone about it at the nursery today. He feels it is bloom-rot. Recommended fertilizing with a phosphorus. Said that should do it. Hope he's right!
I transplanted the astilbe that's in my yard, it was doing the same thing. I felt it was getting to much shade. This year they all flowered, I have them in the shade with filtered sun in late afternoon, this is my third summer and the first time they've bloomed, it might be your problem also.