Why do my Knockout Roses have holes and greyish white spots on many leaves? Also, now they are starting to sprout some red leaves. . . is that normal?
Problem With Knockout Roses
It is hard to say without actually seeing a picture. The holes could be insect damage and the greyish white spots could be the insects if they move. Otherwise it may be a bit of a fungus infection. Spraying with an insecticide of your choice should take care of the insect damage. Be sure to spray up under the foliage too as some insects like to hide underneath the leaves and thus dodge the insect sprays while they continue to do damage. The red to maroon colored leaves are new growth. They will turn green as they mature. Along with that new growth will come more buds for more blooms! That is a good thing indeed!! Oh yes, for the greyish white spots if it is a fungus of some sort, spray the rosebushes down with a fungicide. My favorite and earth friendly fungicide is called Green Cure. It is available on line and at some garden centers and nurseries.