Lettuce salad with perilla. (Barbara Damrosch)

Looks aren’t everything, but every now and then there’s an edible plant that I grow only for the way it dresses up the garden. The herb Perilla frutescens is a case in point. It looks like purple basil redesigned for a flamboyant role in a ballet. As the toothed, heart-shaped leaves grow and mature, they twirl, they flounce, they flash the bright purple underside of their more drab top surface.

The Victorians, who called this beefsteak plant, used perilla as a dark foliage accent among the pansies and begonias of their bedding schemes. I mix it more informally with flowering shrubs such as fothergilla and pink native azaleas. Any tall, leggy plant, whether a cleome, cosmos or long-stemmed dahlia, looks better when rising from a sea of perilla flowing around its base.

And flow it does. Perilla can be hard to grow initially, because the seed must be fresh and must undergo a moist chilling period. But once you’ve got it, it seldom goes away, happily reseeding from flowers borne in late summer. I count on it as a ground cover in a bed where it is well established, and although plants sometimes turn up in unwanted places, it has never been a problem in my yard. (This is not the case in some areas, and if it behaves too aggressively, you had best pick the flowers before seeds can form.)

Asian friends, who call the plant shiso, prize it greatly and often ask for sprigs. As a member of the mint family, it has a decidedly minty taste — along with something more — and is used not only to flavor many dishes but also to color them. The pickled vegetables or umeboshi plums for which it’s used turn a bright purple color. (There is also a green form of shiso, popular in Korea, that has culinary and medicinal uses.)

Regular, purple-leafed perilla is often used in making sushi or sashimi. I like the raw fish idea, because whenever I’ve cooked with purple shiso the color drains away, as with so many foods whose redness or purpleness is a fleeting, water-soluble compound.

When I do use perilla it’s often as a mint substitute, because the bed where it grows is right next to the kitchen and my true mint — a more serious spreader — is colonizing a wet ditch half a field away. I flavor cut-up fruit with perilla or add it to iced tea.

Sometimes it’s a stand-in for red lettuce. I like making a salad with leaves of different shapes, colors and textures. Like a pizza or an open-faced omelet, scattered with this or that, a salad is abstract art. Recently I had a beautiful, pale green head of Boston-type lettuce, and another that was a deep green romaine — a good contrast, but I needed drama. Enter shiso, with a spark of minty flavor and purple petticoats.

Damrosch’s latest book is “The Four Season Farm Gardener’s Cookbook.”

Tip of the week

Poppy seed should be sown now for flowering next May and June. The corn or Shirley poppy is available in red, pinks and whites, and adds a cottage-garden feel to late spring. Scatter the tiny seed onto soil that has been lightly cultivated. When weeding this winter, be careful to leave intact the distinctive serrated leaf rosettes of the poppy seedlings.

— Adrian Higgins