Plant of the Week
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.