My knockout roses wee beautiful last year but have struggled this year. They budded in the spring but the buds never fully bloomed. They turned brown and died. A friend told me to try cutting the bushes way back to see if the needed to rejuvenate. When I did that I was able to see the stems much better. After doing a little research I am now worried that they may have rose rosette. What do you think?
I see no current signs of Rose Rosette disease. The new growth will have a maroonish color to it and then turn as they foliage ages. I would feed them with an organic or organic based rose food. Locally we have two that are very good. One is Gro Rich Rose and Perennial Food by Richlawn. The other is called Mile Hi Rose Food. If you cannot obtain one of those, seek out an organic rose food to build the soils home and nourish the rosebushes. I would also recommend giving them some Kelp meal, about 1/3 cup per bush, scratch into the soils and water in well. Also water the rosebushes with some water that has both a product called Super Thrive and a root stimulator mixed into it. Water them with such mix the next 4 to 5 times they need watering.