Answer: Bud blast is the drying up and failure of flower buds to open. It's a physiological condition with many possible causes, such as root injury, cold soil, high temperatures during cloudy weather, dry conditions during formation, a lack of potassium in the soil, or excessive shading. Do you think any of these conditions are present?
There is also a disease called bud blight, caused by a fungus called Botrytis.
Thrips are tiny insects that sometimes attack flower buds, but it's odd they wouldn't be on all the bushes. Hold buds over a sheet of paper and tap. If thrips are they they will fall on the paper and can be seen. They are about one-sixteenth of an inch long.
It's sometimes difficult to figure out the problem when similar plants are doing well. Sometimes it's as simple as a weak plant that is just a "non-achiever." I suggest taking a sample of the problem back to the nursery, or to your County Cooperative Extension for help in diagnosing the problem. They are at 1200 N. Telegraph Road, Dept. 416, Pontiac, 48341-0416, 248-858-0880. I hope this info helps!
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