I have holes in the leaves on the knock out roses. I have sprayed them with Seven and the newer leaves do not have holes in them. Should I cut the roses back to eliminate most of these leaves. I realize it is too late to cut the plants back and am wondering if it will damage the plants.

Answer #2 · Dave Hunter's Answer · If the holes are circular and seemingly cut out by an insect, this is probably due to leafcutter bees, a beneficial pollinator in your yard. Rose petals are a favorite nesting material! By spraying or placing any chemicals to kill these bees... you are doing much greater damage to your yard than you know. Caterpillars also may munch on your leaves, but they their leaf holes tend to be different than more round shaped leafcutter holes.

The leafcutter uses these leaves for nesting material in their holes. They gather leaves and stuff them into holes about 1/4", fill that little pocket with gathered pollen from your yard, then lay an egg in the pollen. More leaves, then pollen, egg, etc. until they fill that hole. Leafcutter bees are gentle as they have no need to sting.

Here's a website with a few pictures in it... www.beautifulwildlifegarden.com/leafcutter-bees.html)

Answer #1 · Brent Wilson's Answer · I reposted Brooks answer here. He accidentally posted the answer in the Comment section.

The holes may be from late cold snaps. As long as your new foliage doesn't have the holes I wouldn't worry too much. If the new leaves develop holes you will definitely want to inspect the plant for insects. Make sure to look under the leaves. If none are observed it might be a fungus, but this is unlikely. In any event, I like Neem Oil for the treatment of insects and fungus. Neem Oil is organic and safer to use than other chemical products. If the leaves are causing the plant to look bad you can prune them. From experience I have noticed that K.O. Roses handle pruning very well, and at any time of the year. I have a Dbl Pink K.O. Rose that for some reason flushed out with awkward looking foliage this spring. The deer had eaten much of it prior. I cut it back by about 2/3 and have noticed new foliage. I am waiting to see if the foliage is normal. If not I'll be spraying Neem.)