Knockout Rose bush
What can I do about the leaves on my yellow knockout rosebush? The leaves are riddled with small holes and the bush itself is not doing very well. The bushes are blooming, but there are few flowers each year. I have had this bush for about 12 yrs and am so disappointed in it. It was a gift in memory of a deceased member of our family and I hate to see it die. Thanks for any help you can contribute.
Knock out roses are attacked by the sawfly. The larvae eat the leaves membranes and discolor them along with the plants nutrition. Buy neem oil and follow directions. Add some drops of dish soap to mix water and oil. Spray the leaves top and bottom after no sun is on the plant. Prune the plant back casually. Not a lot. New growth should return. Spray this method every few weeks.