Question
I have two groupings of knockout roses and in both groups one of the double red roses has deformities. The new growth is very red with small narrow leaves and small poorly formed buds. The other roses in the grouping (either pink single knockouts or another red double knockout) look great. What is the problem?

Answer
Your rose has a very serious problem called Rose Rosette. It is caused by a tiny mite and will also  infect the other roses . Here is a website that will give you all the information about this problem. The infected rose should be burned or put in the garbage as there is no known cure for the disease.

http://www.ars.org/About_Roses/disease_rosette1.html