Most of my roses are in mixed beds, but the main bed with my hybrid teas has Homestead Purple verbena as a ground cover. One part has 'Kit Kat' nepeta.
I've tried annual alyssum and petunias, portulaca and purslane. One hot dry years, the petunias die. On wet years, the purslane and portulacas die. I never know which kind of year we'll have, so that's why I've gone to using verbena. It's hardy to zone 6, even though some of the literature still insists zone 8.
The verbena works because the dark purple blooms blend well with any color rose, in my opinion.
The bed is edged with iris, so I have color early in the season while roses are still bare. There's a few lilium in there too. It's a trick to water the roses and not the iris and lilium, and to keep the mulch from getting on the iris.
Hope that helps you!
