Silver-leaved plants like Artemisia and sage are heat and drought tolerant as well as being unappetizing to deer and rabbits.
Silver foliage also looks attractive in a garden as it contrasts well with all colors of blooms.
If you need to cover a large area of ground in full sun, Artemisia—hardy to zone 6—is a good choice as all varieties are vigorous spreaders. Beware of placing them in a small bed with other perennials, however, as they are not good neighbors if they don't have a lot of space.
I have an Artemisia in a stone pot on a pedestal in a flower bed where it is confined. It never seems to demand much water and provides a cool accent in the hot days of summer.
Silver curlicue Artemisia with the botanical name of Artemisia versicolor ‘Seafoam' is soft and lacy in appearance and combines well with more stiff and erect perennials.
The better known Artemisia ‘Powis Castle' also combines well with most other perennials, including the giant-flowered purple sage, which is hardy to zone 5.
Lambs Ears ‘Big Ears' is a variety that is low maintenance since it does not bloom, so there's no dead-heading, and it tolerates humidity as well as combining well with any other plants.