The perennial plant, Prunella vulgaris, or self-heal, is both a weed and wildflower. But it really wants to be the perfect groundcover for shady woodlands
Shade gardens give many challenges to the gardener. Areas, where little sunlight shines, can seem bare and dark. The answer is to choose perennial plants that thrive in shade and spread into mat-forming groundcovers. Here’s a plant that’s not very often used in gardens, sun or shade—Prunella vulgaris, self-heal. It may also be hard-to-find in plant nurseries, but tracking it down is worth the effort.
Self-heal, Prunella vulgaris, is an easy-to-grow member of the mint family, well-suited to shade groundcover use. It’s also known as all-heal, heal-all, woundwort, and the delightful-sounding blue curls. This creeping perennial is a cousin of the groundcover bugleweed to which it shows a strong family resemblance. It bears tiny, ‘lipped’, violet-blue flowers on square stems that grow 6-12 inches high and creeps along via underground stolons. Its leaves are semi-evergreen and oval in shape.
It’s true that some gardeners shun self-heal. In Perennials for Shade: Easy Plants for More Beautiful Gardens there’s an article on the related species, also called self-heal, Prunella Grandiflora, (see below.) The author’s advice is, ”CAUTION: Avoid the common P.vulgaris because it is an unimpressive, weedy species.
But in Jekka’s Complete Herb Book, Jekka McVicar praises Prunella vulgaris: “This plant, which is easy to establish, makes a colorful ground cover with attractive flowers … much visited by bees and butterflies.” Also, Gregory L. Tilford, in Earth to Herbalist: an Earth-Conscious Guide to Medicinal Plants, describes self-heal as a beneficial plant being useful as a soil-aerator, attractive to bees, and acting to prevent soil erosion—as well as being a secondary forage plant for herbivores.
Some herb nurseries advise the use of rich organic compost for self-heal to produce a lush, heavily flowered plant. Would this make the difference between straggly weed and magnificent shade plant? Many plants have made the transition from weed or wildflower to garden plant, notably spiderwort, foxglove, goldenrod—why not self-heal too?
Self-heal is a perennial groundcover that, regardless of some remarks to the contrary, can be a welcome addition to the shade garden. It spreads rapidly by means of rhizomes and will blanket an area with a thick, semi-evergreen mat in no time. If more plants are needed, just dig up the larger clumps in the spring or fall and divide. Don’t let it near borders with weaker plants, but keep it surrounded by strong plants such as hostas or larger shrubs. Self-heal blooms for four weeks or more, as the tiny flowers open a few at a time If it’s cut back with a lawn mower it responds by producing thicker, shorter plants that bloom closer to the ground.
Self-heal will grow almost anywhere, but in North America prefers some sun or partial shade in the North and partial shade or shade in the South. It prefers moist, but the well-drained soil of average fertility. Try it as a shady groundcover along woodland paths or in the rock garden. The experimental gardener could also try self-heal in a shady patio planter, where it’s best as a filler plant, not the centerpiece.
Self-heal, Prunella vulgaris is readily available as seeds or plants from wildflower or herb nurseries but less likely to be found in mainstream plant nurseries. There the offering is more likely to be Prunella Grandiflora (large-flowered self-heal). This is the only species available without too much difficulty. Its compact spikes of bracts bear two-lipped blooms in shades of purple, red, and white.
Self-heal is an alien species in North America but is widely distributed throughout. It is listed as an invasive species by the U.S. Forest Service, although only as Category 3 – Widespread Non-native Species, characterized as “not especially invasive.”
In the United Kingdom, Kew Gardens takes the opposite approach and instead of worrying about self-heal being an invasive species, their concern is whether or not it’s a threatened species there. Their conclusion? —No, it’s widely distributed all over the British Isles and has many different habitats.
A Medicinal Look at this Groundcover: Prunella vulgaris in Cancer and HIV Research
This herb has a long history of use in Europe and China as an anti-spasmodic, astringent, diuretic and bitter tonic. But modern science has now taken an interest in it too and there is an increasing number of studies devoted to this plant. In addition to cancer research, HIV studies are underway.
Prunella vulgaris, self-heal, can be a fine perennial groundcover choice for shady gardens. It needs some restraining but is not overly invasive. It provides a quick-growing lush groundcover mat that needs little maintenance. The adventurous gardener won’t be deterred by weedy warnings and will help self-heal make the transformation from wildflower to prized shade groundcover.
~ Jen L. Jones