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U.S. Forest Service

Plant of the Week

Map of the United States showing states. States are colored green where Tweedy’s lewisia may be found. Range map of Tweedy's lewisia. States are colored green where the species may be found.

Closeup Tweedy’s lewisia flowers. Tweedy's lewisia (Cistanthe tweedyi). Photo by Terry Lillybridge.

Tweedy's lewisia growing with small bluebells. Tweedy's lewisia (Cistanthe tweedyi) and small bluebells (Mertensia longiflora). Photo by Terry Lillybridge.

Tweedy's lewisia (Cistanthe tweedyi (Gray) Hershkovitz)

By Terry Lillybridge

Until recently in the genus Lewisia, Tweedy's lewisia is a regional endemic found in north-central Washington and adjacent Canada. This beautiful flowering plant from the purslane family (Portulacaceae) commonly grows on well-drained slopes often on rocky slopes or in rock crevices from low elevation ponderosa pine sites up to the drier part of the grand fire zone.

Tweedy's lewisia is a robust, fleshy, perennial herb from a large, thick, reddish, and fleshy taproot. The leaves are 4 to 8 inches long, fleshy, up to 2 inches wide and narrowing to a somewhat winged stem. The flowering stems are erect and up to 8 inches tall. The flowers are up to 3 inches across and are a beautiful salmon to yellowish-pink in color. It is by far the most showy lewisia and blooms from May to July.

The nursery trade has taken some interest in cultivating Tweedy's lewisia because it is perennial, has showy blooms and it is drought tolerant. This is one of the regions showiest herbaceous plants. Tweedy's lewisia has a limited geographic range but is quite common within that area. Another related and somewhat more common plant is bitter root (Lewisia rediviva), an important part of the native people's diet and fed to Lewis and Clark on their "Voyage of Discovery". Lewisia. rediviva has large pink flowers and small, fleshy linear leaves.

For More Information

PLANTS Profile - Cistanthe tweedyi, Tweedy's lewisia