grassboro:

Long blooming Salvias in Blue,White,light blue.S.guaranitica
Black and Blue keep in mind 1) pine voles love the tubers 2) this one spreads underground. Salvia farinacea "Augusta Duelberg",greggii "Texas Wedding" for plant that don't move around the garden.
S.azurea has reliable cold tolerance mine only blooms in the fall.
The German forms "Blauhugel" & "Schneehugel" for the front of the border. they will need some occasional prunning to
keep them compact.
S.chamaedryoides may need some additional soil amending a
Electric blue flower very nice.
Richard is closer to you I would see what he has to say as well.
Art

S. guaranitica `Argentina Skies' is light blue with a long bloom season. It has tubers also. These can be protected to a great degree by working crushed rock, which will deter the tunneling moles, looking for beetle larvae and earthworms. Voles are weak, and therefore, opportunistic diggers. Plants with tubers generally have evolved in hard plains soils with limestone, or in rocky scree soils on alpine slopes. There is relatively little food for tunneling predators in these environments, unlike forest soils and their accompanying clearings. Xeric plants have often evolved by necessity to have large starch storage organs, and usually where predators are absent.

A lot of bulbs like Colchicum (toxicity) and Allium (obnoxious taste) have other defense organisms. Alliums like onion and garlic are toxic to dogs and especially cats. Salvias are largely deer and rabbit resistant because of strong tastes and bitterness. Often, rabbits and deer will sample sage plants. They will eat them if there is nothing else.

Rich,Thank you for these observations.

Thanks for the comments. They are very helpful. I have also found the web page "Notes on Growing Salvias in Central North Carolina by Will Cook".
The author notes his experiences with Salvis in Chapel Hill, NC, which is where I live. So this is also helpful. I look forward to growing some this year.