Super Sages: Hardy Perennials Make Good Companion Plants

Super Sages
Hardy Perennials Make Good Companion Plants.
By Rachel Foster 4/8/04

New sages for the garden have been introduced so fast in recent years that books on the topic are obsolete as soon as they hit the shelf. Many of these new Salvia varieties -- and some of the most glamorous-- are generally frost-tender plants from Mexico and South America, to be grown, in our area, as annuals. There are, however, many perfectly hardy perennial sages that have a lot to offer as part of a sunny border's supporting cast. By that I mean that while you would not grow them on their own as you might, say, a fine day-lily, they make terrific companion plants. Some are also reasonably tolerant of drought: they do need water in summer, but don't demand consistently moist soil.
Hardy sages are a reliable source of blue and purple. Only a handful have flowers of pure, spectrum blue; most are purple, lavender or violet. A few are pink or white. Some form rosettes of leaves the first year and bloom the next, and after that they are not good for much; but the real workhorses of the salvia world grow in slowly expanding clumps that can be left in the ground from year to year or divided to make more plants. I won't spend time on the rosette-formers, except to say that everyone should grow Salvia argentea at least once! The rosette is big and covered with brilliant silver fur. The following spring, if it survives the winter wet, it explodes in a mass of bloom about three feet high.
The true perennials among herbaceous (non-woody) sages carry their small, hooded flowers on vertical spires that look wonderful intermingling with lilies, daylilies, phlox, kniphofia and daisies. Some of the best are hybrids that you will find labeled Salvia x sylvestris as well as a variety name. Probably best-known of these is 'May Night.' For years it was called 'Mainacht,' and it was a connoisseur's plant. Then some bright nursery person translated the name and promoted it as Plant of the Year.
Once May Night became popular, some unscrupulous growers began to stick the name on any variety they wanted to move, and you may now find at least two distinct plants under this name. The one I currently understand to be the genuine article has pronounced, sturdy basal leaves so pungent that deer usually leave them alone. Violet flowers in dark calyces are carried on two-and-a-half foot stems. 'Indigo' (not to be confused with 'Indigo Spires,' below) is more vigorous, and a little taller. The flowers, carried on a more open branch pattern, are light violet and the calyces are green.
There is a group of smaller sages that are useful near the front of a flower bed. Salvia nemerosa ("East Friesland") has many parallel stems bearing purple flowers with reddish calyces, a vibrant color combination. "Blauhugel" ("Blue Mound") is exceptionally compact with flowers more blue than purple. "Snow Hill" has pure white flowers. Last year I enjoyed a new variety of S. nemerosa named "Caradonna," with purple flowers on stems that are almost black. The clumps are coming back strongly. When S. nemerosa stops blooming, cut the plants down within a few inches of the ground and feed them. They will soon bush out and flower again.
According to the gardening literature, Salvia nemerosa varieties are supposed to grow to two feet, but they never do so in my garden, which does not have the light soil they prefer. Clumps expand slowly (they are among the few border plants that I almost always plant in groups of three or more) but they will grow more vigorously if you divide them now and then. Slugs love to eat the new shoots of sages, so in late winter it's a good idea to clear the crowns of any accumulated debris where slugs could hide out.
A relatively recent introduction, Salvia verticillata ("Purple Rain") seems to be particularly tolerant of dry soils. For me it grows about 15 inches tall and twice as wide. The leaves are fuzzy, and the deep purple flowers are arranged in distinct whorls on the stems. Even newer is a hybrid named "Indigo Spires." I have never grown this one, but it is creating a bit of a sensation in the Pacific Northwest, where it appears to be winter-hardy, in spite of having as one parent mealy sage, a familiar tender perennial that most gardeners know in the form "Victoria Blue." "Indigo Spires" makes a bushy, leafy plant from three to five feet tall, and blooms all summer.