It appears as if something is eating the leaves on my bushes. There are multiple holes in all the leaves. What could it be?
It is likely a beetle of some kind causing the problem, there are times when the wind whipping the foliage around can cause the thorns on the rosebushes to poke and tear the leaves. However in your case it sounds like a beetle issue. I would recommend spraying the rosebushes with a good insecticide, perhaps one that has systemic properties would be a good idea to deal with them.
I need my roses to be in full bloom for my daughter's wedding Sept 17. I live in northern Kentucky. What can I do to make that happen?
It is difficult to get rosebushes to cycle their blooms as needed sometimes. However Knockouts bloom very well, so it is possible. Once the roses have bloomed and died back, prune off the spent blooms directly below each bloom. This will leave little stems sticking up. This seems to hasten the onset of the new growth that will produce the new buds and blooms. Keep the rosebushes watered well and fed well. Use a product called Super Thrive in the water the rosebushes are watered with. This helps them deal with any heat or other stresses that could delay blooming.
Can I replace knockouts with more knockouts? How much soil should I remove? If knockouts are not a good choice, would drift rose be okay? If not a rose, what would be a good substitute where knockouts once thrived?
I would recommend removing as much root material as possible when removing the infected rosebushes. I also recommend spraying the entire areas plantings with a miticide that is labeled to kill the tiny eriophyid mite (Such as one called Avid) as they are thought to be the main spreader of the deadly virus. I would remove the soils in a 20 to 24 inch diameter and 16 to 18 inches deep. Replace those soils with a good bagged garden soil that has compost in it, such as one of the EKO brand mixes at Lowes or Home Depot. Replacement roses using Knock Out roses or the wonderful Drift Roses would be fine. Also take a look at the Weeks Roses Home Run series of roses.
My knockout rose bush was cut very low to ground level. Will it return next year?
In my area many rosebushes die back to within a couple inches of the ground many years. They typically come back very nicely if they were healthy going into the winter season. Knock Outs are known to be exceptionally hardy rosebushes, so they should come back just fine.
When should I feed my knock out roses for the last time this year?
I live in zone 5 Colorado. The last time I fed my rosebushes was the first part of September. It is way too late to be feeding them now if you are in a cold climate area. We want the roses to be gearing down to go dormant for the winter. If they are growing too hard when the deep cold hits it can kill the bushes. You can scratch in a couple tablespoons of super phosphate into the soils around the rosebushes. It moves slowly through the soils and gives them a kind of winter snack to keep the roots healthy.
In Kansas, do I need to protect the bush in any way in the winter? I am speaking about the knock out roses. Thank you.
Here is a link to an article I wrote about winter prep/care for rosebushes that would apply to Knock Outs as well. I am in Colorado. Link: https://www.gardeningknowhow.com/ornamental/flowers/roses/roses-winter-care.htm
I live in Clearwater Fl...west coast of Florida and am concerned about some salt spray from the Intracoastal waterway.
No roses really handle salt well. The Knock Out and Home Run lines of rosebushes are very hardy rosebushes and will handle the conditions better than most other varieties. I would recommend planting a couple of either line of rosebushes and see how they do, plant them in an area that is the most protected from the spray as possible.