I have exactly the same problem, and have never seen this before this year. I have not heard of Botrytis - is that something a fungicide will get rid of?

It could be thrips. Do you see little worm like insects in the petals (if it's a dark red rose, you may not be able to see them. Either that or the buds are balling before they open. I too have that on some of my roses.

If it is brown all through the flower, brown areas down to the base, and maybe kind of mushy, that's Botrytis. If it is just the edges of the petals, and if you shake the flower over a while piece of paper and see tiny dark speck-like insects, that's Thrips.

Botrytis goes away with warmer, drier weather; a fungicide would help. Thrips is tougher, you must insecticide the blooms themselves, which may kill bees. It is easier to choose varieties that do not show thrips damage--the flowers may be full of them but the roses look fine.

Amy..I am in Upstate N.Y., also..you don't have an e-mail address on your my page..i do..send me an e-mail..maybe we're close..i'd like to know if we're in each other's back yards! Donna

If it has been raining, often the two problems are present at the same time. Thrips abrade the petal surfaces and probably encourage fungal attack. Botrytis spreads with rain in cool weather. In my garden, thrips peak late in the first flush and then subside as predators build up.

In dry weather, thrips damage is easily identified as dry, brown petal edges and scratches on pale petals.

Larger brown rotten spots on petals are caused by Botrytis. It also causes pink spotting of pale roses. In severe cases, the bud balls (fails to open) and rots. Spores of this fungus are everywhere in favorable weather.

Thank you everyone for your responses. I will have to examine closer re: botrytis versus thrips, although I'm sure I have both in abundance lurking around the garden.

jplamp: Botrytis is a fairly common, I guess, fungus which infects roses. I'm am going to try an organic fungicide, Serenade, on my roses.

Donnaz5: I'll send you an email.

Michaelg and everyone: I've purchased something called "Serenade" (Bacillus Subtilis) for the Botrytis on my roses -do any of you have any experience with this? I thought that next year in early Spring I'd rough up the surface soil and actually apply some to the soil, as I understand Botrytis survives winter in the soil. Would this hurt beneficial fungi/bugs? Any thoughts?

Amyjean, I think you should use the product as it is labeled to be used. I don't know whether it will help. Spores of Botrytis are everywhere in the environment, so I'm pretty sure scratching the material into the soil would be a waste of money.

Hi Amy,

I live in upstate NY as well. My email address can be reached on My Page, if you'd like to compare notes on growing roses in our area.

Botrytis blight is also known as "gray mold". It's caused by a ubiquitous fungus named Botrytis cinerea. The spores are always in the air and will germinate on succulent thin plant tissue (did I just say rose petals? ;-) ) if the tissue stays wet, or at least damp, for 24 hours when the temperature is cool (50's-low 70's, IIRC). There are fungicides that will kill it, although I am no longer familiar with which are recommended for the home garden.

If the plant tissue's surfaces dry out enough or the temperature gets warm enough the spores won't germinate, or will fail to thrive. It's an opportunistic fungus that needs a particular set of weather conditions to grow.