Question
Hi, My mother has a large rose garden with different varieties.  However, she has one rosebush that is thornless (all the others have thorns) and this bush has rosebuds that blossom but do not open.  It has happened for a few years now since she planted it.  The other bushes blossom wonderfully...

Answer
When a rose bud doesn't open it is usually caused by a couple of insects. One is a Thrip and you can tell if it is a Thrip because when the flower does start to try and open, it will have brown pin holes on the edges of the petal and also on other areas of the flower. The other is a Rose Midge which lays it's eggs at the base of the rose bud and when they hatch they feed on the buds and damaged them so they can't open. If you look closely at the base of the buds you should see a tiny little hole near the base if it is a Rose Midge that is causing the problem. If it is one of these pests look for a rose spray that has these insects on the label and use accordingly.