SHOWSTOPPERS FOR YOUR NOOKS AND CRANNIES
Following are Harvey Wrightman's plant picks for a beautiful, crevice-garden show.
Rock jasmine (Androsace sarmentosa) A popular Himalayan species with grey, woolly rosettes that spreads slowly to hang over rocks; covered with carmine flowers in May. Hardy to Zone 3.
Sandwort (Arenaria tetraquetra) Succulent, hard, scale-like mats of tiny green leaves; stemless white flowers in spring. Intergrow with bulbs for an interesting tapestry effect. Hardy to Zone 3.
Woodruff (Asperula gussonii) Mounds of dense, silver-frosted, dark green leaves; stemless pink flowers in late spring or early summer. Hardy to Zone 5.
‘Dickson's Gold' campanula (C. garganica ‘Dickson's Gold') Outstanding for its bright gold foliage, it also has light blue, star-shape flowers in summer. Hardy to Zone 5.
‘Sooke Form' shooting star (Dodecatheon pulchellum ‘Sooke Form') Short stems erupt into large, magenta flowers in mid to late spring. From the high altitudes of Vancouver Island, this is the most spectacular of dodecatheons. Hardy to Zone 5.
Rock stork's bill or heron's bill (Erodium petraeum spp. crispum) Although delicate in appearance with its lacy foliage, this erodium prefers full sun, wind and rocks. Flowers are white with dark purple veins; blooms non-stop from June to October. Hardy to Zone 6.
Siskiyou bitterroot or siskiyou lewisia (Lewisia cotyledon) Wonderful, succulent rosettes with a long succession of shades of pink to red-orange in late spring to early summer. Hardy to Zone 6.
Linum hirsutum This new flax has woody stems clothed in soft, hairy leaves. Large amethyst flowers are produced from July until frost. Hardy to Zone 5.
‘Airemist' primula (P. allionii ‘Airemist') A new alpine primula that has compact, delicate-toothed leaves with large, stemless flowers of purest white in early spring. Hardy to Zone 4.
Veronica bombycina A mat-forming, stunning plant with tiny, silver-felted leaves; covered with pure blue flowers in May. Hardy to Zone 6.
In addition to true alpines, which are native to mountainous areas, a wide range of plants thrive in a crevice garden: miniature bulbs, cushion or mat-forming perennials and wildflowers are good candidates. Dwarf evergreens and slow-growing shrubs provide visual and physical anchors for the garden. An important characteristic of a crevice garden plant is its appropriate scale.
Choose plants that prefer a sunny, open location-and also require good drainage, although one of the advantages of individual planting pockets is that soil conditions can be tailored to each plant's requirements. Gravelly soil provides the aeration and excellent drainage that the roots of alpine plants require to survive. Harvey Wrightman recommends adding a 10-10-10 or 15-15-15 liquid fertilizer early in the season to boost growth in the peak flowering months.