Native to Southern Oregon and Northern California, Lewisia cotyledon, or Siskiyou lewisia, is a subalpine succulent featuring a spectacular array of color when in bloom. Of them, the award-winning ‘Rainbow’ variety of this species boasts the largest range of flower color in cultivation, including white, yellow, pink, red, orange, purple, pinstriped, and mixed. Large clusters of 7 to 13-petaled flowers rise up from the plant’s basal rosettes on 4 to 12-inch tall rigid stems. Beginning in mid spring, this plant will bloom for about a two-week period, then continue to rapidly rebloom all the way until mid to late fall. In my unheated greenhouse, I’ve actually had them bloom year-round.
At the base of the plant’s fleshy 3-inch leaves, new plants will slowly offset, forming a clump over time. Drought and cold tolerant, Lewisias are an excellent choice for containers, patios, rock gardens, and for the cracks between rocks in a retaining wall.
Like all Lewisia cotyledon, Rainbow lewisias need good drainage. I have no trouble growing mine in a variety of locations in the fairly (seasonally) cool and wet Western Oregon, including containers (both outside and inside a greenhouse), planted in sandy mounds, and planted on a slope with partial shade. I lightly irrigate mine in the summer to promote summer blooming, but allow them to dry out between waterings, as excess summer water will cause this species to rot. Lewisia cotyledon should survive a complete summer drought unirrigated; however, without the light irrigation it will cease flowering until the next rain. This species will grow in conditions ranging from full sun to dappled shade.
Rainbow lewisia ships in a 1 quart round pot.
- Max height: 12″
- Max spread: 12″
- Hardiness: USDA Zones 4-9
- Light: Full sun to part shade
- Water: 1x per month in summer, natural rainfall is sufficient fall through spring; in particularly dry climates, water 2x/month fall through spring
- Soil: Well-drained, pH 5-7
- Wildlife: attracts pollinators, deer-resistant