Seems some type of insect is feeding on my knockout rose Bush. Small holes all over bush. What to do?
I would recommend buying some Bayer Tree and Shrub granules. Apply the product around each rosebush working it into the soils as directed on the label for ornamental shrubs. Water in well. This product has done very well for me and one application per season is all that is needed typically. Where sprays can sometimes not get at the culprits that hide under the foliage, this systemic gets at them by moving throughout the bush in its natural juices. I also recommend working some good compost and alfalfa meal into the soils at least once per year to help keep the rosebushes soils home healthy for their roots.