Some of the most stunning plants grow under the most trying conditions. Breathtaking waterlilies (Nymphaea spp.), for example, thrive with most of their mass submerged below water. Lovely bulbs hail from lands with searing summers. And many rock-garden plants cling to life with scarcely a foothold, yet bloom with striking beauty – the stonecrops being a particularly fine example. British Columbia, being a land of mountains, is a land of rocks, and thus home to several of these attractive yet tough rock plants.
Broadleaf stonecrop (Sedum spathulifolium) is an exceptionally handsome and abundant rock plant in coastal B.C. This perennial herb typically grows as a loose mat of exquisite grey-green to dark-red rosettes of leaves. Each rosette (two to four centimetres in diameter each) consists of about 15 flattened leaves arranged in rings around a central point. The rosettes arise along a creeping stem called a stolon. At each growing point of the stolon, a few straggly roots cling tenaciously to rock surfaces and shallow soil. The flattened fleshy leaves broaden toward the tip and help the plant store water to survive the hot, dry summer season.
This stonecrop flowers in B.C. from May to July, when flat, brilliant-yellow flower heads adorn stiff stalks that stand 10 to 15 centimetres above the leafy mat. Often, many flower heads arise from a mat of leaves scarcely 25 centimetres across. Small star-like flowers, each with five petals, crowd together in the flower head, while a cluster of stamens and stigmas occupies the centre of each bloom.
Though several native B.C. stonecrops grow in the interior and even on mountaintops, broadleaf stonecrop is a coastal inhabitant. You will certainly encounter it on cliffs and sunny rock faces all over Vancouver Island and the Gulf Islands. It occurs widely, but less frequently on the adjacent mainland, its range extending southward to California. Look for it along the shore and in rocky forest openings, even well up mountain slopes.
This stonecrop excels in dry garden sites. Take a tiny piece of rooted stem, or larger mat if available, and plant it on, not in, shallow, well-drained stony soil. Try it in your rock garden, next to a stone or gravel path, or tuck it into a crack in a rock, brick or cement wall. Once it takes hold, this plant will spread quickly, filling the spaces between rocks and carpeting rough spots. Although broadleaf stonecrop prefers full sun, it will tolerate light shade, forming a loose mat of rosettes. Its yellow flowers provide a surprisingly bright display in the muted light of a forest glade.
Stonecrops are easy to care for once established. Remove dead stems after flowering for a neat look and keep grasses from rooting in the mat. As your patch expands, it produces plenty of offsets. Under good growing conditions, a small piece may double in size after a month and quadruple the area it covers within a season.
Broadleaf stonecrop is generally available at garden centres and nurseries. In addition to the typical form with greyish-green leaves, you may find reddish, purplish (variety purpureum) and greyish-blue forms, as well as a grey-white variety called ‘Cappa Blanca.’ In fact, you could create a rock garden of varying hue by planting several different colour forms.
B.C.’s First Peoples had several interesting uses for broadleaf stonecrop, from treating piles and relieving constipation to easing childbirth and calming cross babies.
For those of you with gardens away from the mild climate of the coast, consider either lance-leaved stonecrop (Sedum lanceolatum) or spreading stonecrop (Sedum divergens). Both species bear yellow flowers and grow in the wild in sites ranging from lowlands to mountaintops. The rounded bright-red leaves of spreading stonecrop look almost like berries. Although the leaves of all of our stonecrops are edible, they should be consumed in small amounts, as too much can cause headaches, diarrhea or vomiting.
While you may not grow them for eating, welcome native stonecrops into your garden and you too can bring life to cold hard rock. With their brightly coloured flowers and variously hued leaves, these plants will decorate walls, rocks and stony paths throughout the year.
The following plants are hardy up to the zone number indicated:
• Broadleaf stonecrop (Sedum spathulifolium) – zone 5-6
• Lance-leaved stonecrop (Sedum lanceolatum) – zone 0
• Spreading stonecrop (Sedum divergens) – zone 0
An expert on native plants, Richard Hebda is curator of Botany and Earth History at the Royal British Columbia Museum in Victoria.