Lewis’ monkeyflower brings bold pink to Mt. Hood’s mountain streams in summer. Clumps of leafy stems, often one to three feet tall, line creeks and wet meadows, and each stem carries large rose-pink to purplish flowers, about one and a half to two inches long, marked with yellow in the throat.
The plant is named for Meriwether Lewis. The Lewis and Clark expedition was the first to record it, near the headwaters of the Missouri River, and the botanist Frederick Pursh named it in 1814. The older genus name, Mimulus, comes from a Latin word for a comic actor: Linnaeus thought the two-lipped flowers of these plants looked like a grin, and the name monkeyflower probably comes from the same grinning face. Many guides still list it as Mimulus lewisii.
Bees pollinate the flowers. The whole plant is sticky and hairy, and it grows from stout, branching rhizomes, so its stems come up in clusters. Its size and big pink flowers make it one of the easiest monkeyflowers to identify.
Look for it from early summer into August along streams and in wet meadows at middle to high elevations, often among rocks and boulders at the water’s edge.
How to identify it
Clumped, sticky-hairy stems 1 to 3 feet tall with opposite, stalkless leaves that have several prominent veins from the base and toothed to smooth edges. Large, two-lipped, rose-pink to purplish flowers, 1.4 to 2 inches long, marked with yellow, borne singly on long stalks from the leaf bases.
Habitat
Streambanks, wet meadows and rocky creek edges at middle to high elevations in the mountains, occasionally lower along rivers. It ranges from southeast Alaska and Alberta south to California, Utah and Colorado.
Sightings in the forest
366 research-grade sightings in Mt. Hood National Forest on iNaturalist, most recently on September 22, 2026. See them on iNaturalist →