Aunt Lou,

Salvia nemorosa 'Caradonna' is indeed a good plant, and very hardy. In England it grows to just under 2 ft. Its flowering season is mostly over by the end of July, but given a good chop, it often has a second flush in September. I reckon that it is better than May Night or East Friesland. You could also try Salvia pratensis 'Indigo', this is a stunner, tall, and very long-flowering, but it is more indigo than purple.

Not a Salvia, but you could try the annual Zinnia 'Purple Prince', this could be a nice combination with your roses.

You might also consider another agastache, such as 'Purple Haze' or 'Black Adder' . Blooms all summer, drought tolerant, deer, rabbit resistant. Loved by butterflies. You may be pushing the zone, but since you grow 'Blue Fortune', these might work for you.

I have 'Caradonna' and it is a great salvia, but requires cutting back at least 3 times in the summer for blooms.

An annual salvia, like farinacea 'Victoria Blue' is beautiful. I grow it with just about anything, including my roses. It is spectacular.

Cameron

Here is a link that might be useful: six of my agastache varieties