Joanne, Mine are doing the same thing. Prairie Star, a white Buck barely opened and some are brown buds. I wonder if it's a combo of something. I'm thinking of the people who grow Buck's in TX and their heat, and what theirs are doing.

Carla

Carla--the offenders in my garden are primarily Etoile de Lyon, Souvenir de Pierre Notting and Coquette des Blanches, though there are a few others that exhibit some of this behavior. The leaves and general health on these three roses is superb, which makes me think it is not a drainage problem. Maybe it is just a reaction to the high temperatures?

What do thrips look like? I have not noticed any bugs, but I will try the 'shaking a bloom over a piece of plain white paper' suggestion to see what happens. Thanks Berndoodle.

Actually most of my blooms look like small globs of mushy toast.

Carla

Berndoodle--I tried your 'shake the rose' method of insect determination and found that there were in fact about 2 or 3 brown slithery bugs about 1 mm long. Without a magnifying glass I could not see any details, but they crawled in a very snake-like fashion across the paper towel. They did not fly off the towel, however. Are these thrips?

Sounds like it. Not only are they a bane to roses, they can also invade LCD monitors.

There are several thousand different species of Thrips.

Here is a link that might be useful: Thrips in LCD monitors

'Some plant-feeding thrips are also predaceous on other pests, such as spider mites. In young cotton seedlings in California, western flower thrips is considered beneficial because it feeds on spider mites.'

Here is a link that might be useful: Thrips info at UC Davis

jbfoodie, in the larger scheme, 2 or 3 thrips isn't anything. Try again at a different time of day and look for an open bloom with many petals and a light color. Then choose a dark red or deep pink bloom and do the same thing. At times I can see a dozen or more thrips on the paper. The interesting thing is that the dark blooms will have just as many thrips but show little damage. It's something in the pigment. The two signs of heavy thrips is balling in the middle of conditions where there hasn't been rain or other heavy humidity to blame and light blooms showing the effect of dark brown on the petals' edge, as if burned with a blow torch.

In my gardens, I see no thrips damage until late June. It lasts through August or so. The mid-September through October flushes are again fine. My gardens both adjoin large areas of dry grasslands that dry out by mid-June. My impression is that those meadows act as thrips breeding grounds and that once the summer foggy winds start blowing the thrips are blown into my gardens. I once tried - - exactly one time - - to spray for thrips. Hah! What a fool's errand. Between the wind, the 5 day spray cycle, and the suggested spray application on the buds only, I realized I didn't want to be that deeply involved in the day to day interactions between my roses and their bugs.

My garden areas with a sizeable irrigated garden buffer between the roses and the grasses are much less troubled by thrips. Or maybe it's the direction of the wind - the roses on the western edge screen out all the thrips, and by the eastern edge, there are very few. They are a pain, but much a less a pain with many deep pink or red roses, that can be crawling with thrips, still open and show only minimal scorching on the petal edges.

Berndoodle--I have noticed some balling in the hot summer months here. The buds are brown on the outside. It does seem to start around June. I am in a suburb surrounded by dry hills. Perhaps this is how they are making it to my garden. It is little enough damage really. The deer are far more destructive on the roses in my front yard than the few summertime thrips. I will just put up with it as I am not about to start spraying. I will check out the pinks and reds as you suggest. Thanks.

That's pretty interesting, Berndoodle. I've always wondered how thrips can be selective about color when I think they get into the buds before they open and show any color. I've seen thrips on dark roses too...I think you're right that the dark ones just don't show damage as much.

I'm getting balled blooms and brown edged ones too.

hoovb--it may be that these are the 'Western Flower Thrips.' The coloring sounds like the description at the website you posted. I do have spider mites, so maybe these will be somewhat helpful.

I noticed this morning that zillions of thrips were crawling all over my Kronprincessin Viktoria, but for some reason these blooms show very little damage. The insides of the blooms were definitely beginning to brown, but the rest of the petals looked just fine. At least now I know why my roses look this way.