Question
I planted approx. 200 white carpet roses last May 2008.  The first summer I lost approx. 30 from lack of water.  I replaced most of them and now this summer I losing them again but the soil is moist around plant but the leaves are yellowish and sparse looking. When I dug around base there is white mold on soil from decay (i think) of bark? I love these guys but feel I'm fighting an endless battle.  The soil is a clay mixture.  I live in Central Valley in CA and we are going on record number of days of 100 or better!  Thanks for any advice you may have!  Fredna

Answer
This summer was not a good summer for anyone to plant roses or for that matter anything. It got too hot for too long. Sclerotinia sclerotio  remains in the soil during the winter and germinates in the spring through one of two methods. It may form small mushrooms that release spores into the air to infect plants, or it may form a mycelium, the vegetative portion of a fungus, that directly affects the roots of nearby plants. The latter sounds like the way it survived. Sometimes this fungus just remains on dead material but it can become deadly to plants nearby. I would keep an eye on it to make sure it doesn't get a hold and destroy the rose roots. It would be a wisdom to use a fungicide to get rid of the white mold. Funginex is one of the best if you are able to get it. Use it until you are sure the mold has gone and again next spring in case it returns because you didn't get all the spores.
You are not alone in having major problems with just planted roses or even young transplants. This was a horrible year and so many roses just up and died. Next spring cut all the roses back to about 12 inches and make them start again. This will activate them into better and more vigorous growth. As you probably already know, rose can jump back from only an inch of canes. The White Carpet roses are not as sturdy as the original pink ones but are still a very good rose. They usually grow to about 2 feet tall.