I know that when KO was first introduced, many vendors were selling it as z5 & sometimes z4 hardy, but that didn't prove to be correct. Since you live in northern VA, you maybe in a zone where KO is hardy with minimal or no winter protection, I'd be interested in hearing from other zone gardeners to find out where KO becomes winter hardy without protection. As far as pruning goes, I usually leave every thing until spring to see what mother nature left me to work with.

They should be fine. Yes, the leaves will fall off. You put two inches of mulch around them. Dont water unles you get no snow/rain.

My Knock Outs only get protection from any leaves that might happen to collect at the base. Yes, they experience winter dieback in my zone 5a but they recover quickly.
I leave them alone and prune in the spring.
In Virginia, they may over winter better and I doubt you need to do anything special

Almost no dieback here in zone 6. I prune KO's just to keep them under control.

Here in Zone 5 Central Illinois, my KO's keep their leaves until late Winter for some reason and then fall off. I don't winter protect at all, but do get some cane dieback which I prune off in the Spring. As Karl said, they recover quickly. Last year I pruned them down to about 2' and they were about 4'x4' by the middle of summer. They get stronger with age also.

Leaves may or may not go, depends on general temps during winter. No protection. Prune in late March, hedge clipper works well.

They should be fine. Of course, if you still feel guilty about them, pull in a little mulch around the bud unions, but otherwise not to worry. This is one hardy rose.

Mine get nothing. I don't cover them at all and they do fine!

I'm not sure what your zone is in northern VA, but I doubt you will need to winter protect. I don't have winter protection issues with my Knockouts here in zone 6b but I'd like to address pruning. I left mine alone for 3 seasons but now regret not pruning last spring as they only now bloom at the top and are taller than I wanted for the space I planned for.

This rose will also hold onto its leaves longer than most cold-hardy roses. Don't worry about that, they will fall on their own eventually. In fact, the cardinals love using it for cover when they come to visit my feeder. They seem to like it even more than the native shrubs around it!

I suggest waiting until early spring, which is from Valentines Day until Easter here, and then thinning out some of the the inner twiggy growth and shortening the shrub by one third at the most. This rose gets such a complete coverage of leaves that the inner growth tends to die out for lack of sunshine. And like any other landscape shrub, the lower branches will die if they do not get enough sunlight. Think wider at the bottom than the top to shape it.

I didn't appreciate the Knockout clan until I saw what great 'doers' they really are. It kept them from my shovel more than a few times. They really are the easiest roses to grow, so enjoy!

For the record, Knock Outs are not hardy roses. One of their problems in the cold is that they don't go dormant, so aren't prepared to handle real sub-zero temperatures.

However, that shouldn't be a problem in NoVa.

Here they did get a bit of winter cane damage but once pruned they bounced right back. One thing is they did have dieout in the center of the bushes which had made them look very straggly... any help for that?

Truly, are you talking about dieback in the middle during the summer months?

yes, during the summer the centers really died out leaving them very straggly looking. They used to be super full.... is there anything I can do now? They look awful and were very poor producers this past summer. ~truli

Truli, I have grown Knockouts for several years as hedges; have both the pink and red and mine have never had the centers dieout. I do prune them back severely every April to just about 2', almost like a HT. They seem to really respond to this type of pruning and grow back quickly; I also trim them periodically during the summer and deadhead.

Are you doing any pruning to them? Maybe there's some dead wood left over from the winter that's not getting cut away, thus leaving the dead centers. Just a guess, though.
-terry