Mountain High

Credit: Richard Hebda

Wandering the starkly beautiful high alpine of British Columbia’s mountains, it is hard to believe that some of the tough scattered plants are suitable for our gardens. Here and there are spots of bright mountain harebell (Campanula lasiocarpa), a dash of yellow groundsel (Senecio) and splash of pink river beauty (Epilobium latifolium). Among the most widely grown of these is moss campion (Silene acaulis) of the well-known pink family (Caryophyllaceae).

Moss campion forms a firm mat over the ground, arising from a woody root with a branched crown. A colony may consist of a few stems spreading scarcely 5 cm (2 in.) across to great green patches stretching for half a metre (20 in.) as if flowing upon the ground. Numerous, densely packed short shoots arise from the crown branches, reaching scarcely 3 to 6 cm (1 1⁄2 to 21⁄2 in.) tall in the wild and rarely to 15 cm (6 in.) on robust garden plants. Tiny, narrow to slightly lance-shaped leaves only 4 to 10 mm (1⁄8 to 1⁄2 in.) long surround the stem tip, packed upon the leaves of previous years. This attractive condensed growth form protects living tissues from the bitter-cold, drying winds of arctic and high alpine environments.

Single pale- to bright-pink flowers sprinkle the surface of the mat. Each centimetre-wide (1⁄2-in.) bloom consists of a pinkish to green sepal tube surrounding five petals. The petals have a narrow base that flares into a broad, often-notched, showy tip, a form typical of other campions and members of the pink family. You may just be able to see a pair of little pouches at the base of the wide part of each petal. Plants are often either female or male. Five long and five short stamens are easily evident in males, whereas three stigmas crown the capsule-to-be in the throat of female plants. There are two botanical forms of moss campion recognized, a slightly more robust form with flowers on short stalks native to the southern Rockies and into the U.S. and a more compact form typical of colder regions.

Moss campion is one of our province’s most wide-ranging plants, occurring in all parts of B.C. except the boreal forest zone of the Peace River area. Globally, moss campion ranges around the polar and mountain regions of the northern hemisphere and is well known in Europe and the Arctic, where it occurs to sea level. In the south, the habitat is mostly high mountains above the tree line, but the farther north you go, it appears well below tree line. I know moss campion best from the rocky, frost-shattered landscape of B.C.’s interior peaks, where it thrives on exposed gravel, in bedrock cracks and on alpine turf. It also grows, especially in the north, on river gravels and in front of melting glaciers.

The habitat of this species clearly reveals its suitability as a rock-garden plant. However, there are mixed views as to its qualities. C.L. Hitchcock and A. Cronquist in the classic work Vascular Plants of the Pacific Northwest and A. Kruckeberg in Gardening with Native Plants in the Pacific Northwest extol its virtues. Other authors are less than enthusiastic, being critical of its shyness to flower. But there is no question that moss campion will grow well in lowland gardens given moist, gravelly or stony soil with good drainage and full sun. Colonies expand into wonderful firm green mats conforming to the surface of the ground, a highly valuable characteristic in my opinion. It may not flower as profusely as it does at alpine heights, but when it blooms the bright-pink flowers tossed upon a green mat present a truly enchanting spectacle.

Various forms of moss campion are available through garden centres and specialist nurseries. It also grows relatively easily from fall- or spring-sown seed, by rooting stem tip cuttings in late summer and fall, and crown divisions. Likely the best plants for the garden come from tried and true nursery plants or low-elevation populations, rather than wild material from the rarefied atmosphere and bitter cold of the alpine zone.

Icelanders and a few Arctic folk occasionally cooked and ate this meagre plant. But you should know it contains saponins (soapy compounds) like those used by bush experts to stun fish in wild streams and ponds. Best to enjoy it as a wonderful groundcover in your alpine garden.

The following plants are hardy to the zone number indicated: Campanula lasiocarpa (mountain harebell) – zone 0 • Epilobium latifolium (river beauty) – zone 0 • Senecio (yellow groundsel) – zone 3 • Silene acaulis (moss campion) – zone 0

An expert on native plants, Richard Hebda is curator of Botany and Earth History at the Royal British Columbia Museum in Victoria.