Do you have thrips?
Adult thrips are tiny, slender insects, 1/25 inch long, variously colored pale yellow, black or brown. They have four long narrow wings fringed with long hairs and very short legs. Their chief target is the rose bloom, especially the red, white, yellow, and other light colored varieties. Flower thrips and tobacco thrips attack rosebuds and disfigure petals. They attack buds in their early stages, working among the unfurled petals. The buds become deformed and fail to open properly, while the damaged petals turn brown and dry. New growth also may be damaged in the same way.
Since thrips burrow deep between the petals, early identification and control is important. Set out yellow sticky traps about 4 weeks after last frost as early warning devices. As soon as you spot thrips on the trap, spray rose buds with insecticidal soap or a pyrethrin/pyrethrum insecticide product as directed on their labels. Commercially available predatory mites, lacewings, ladybugs and beneficial nematodes are effective backups to the soap spray. Thrips prefer a dry environment, so make sure plants are adequately watered.
Here is a link that discusses the identification and control of thrips: http://www.ipm.ucdavis.edu/PMG/PESTNOTES鈥?/a>
Do you have leaf skeletonization too?
This could also be an early infestation of Japanese Beetle. They will eat flower petals in addition to the leaf, but not the leaf veins. They love roses and anything in the rose family. Here is a link that discusses Japanese Beetle: http://www.urbanext.uiuc.edu/bugreview/j鈥?/a>
Anything with carbryl like Sevin can be used to control Japanese Beetle. Just be careful with carbryl, it is deadly to bees!Is anyone having a hard time getting their Knockout Roses to bloom this year?
Mine are blooming. I live in Kansas and the only thing that I've noticed eating them at times are the deer.
Try giving it a foliar feeding weekly.
ours are blooming just fine....
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