Salix prolixa
Mackenzie's willow
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Family: Salicaceae · Type: Shrub / Tree · Native
Salix prolixa (Mackenzie's willow) is a native California shrub / tree in the Salicaceae family, recognized by but distinctive large size, serrated leaves, and glabrous undersides.
Mackenzie's willow is a California native shrub found in the Klamath Ranges, northern high Sierra Nevada, and northern Sierra Nevada in banks of rivers, streams, and marshes at elevations of 110 to 2,255 meters. Flowering from March to June, this willow produces yellow-brown flowers on leafy shoots with wavy-haired flower bracts. Growing to less than 5 meters tall with distinctive yellow- or red-brown twigs that are either glabrous or long-shaggy-hairy, it has a distinctive branching habit. Its leaves are narrowly oblong to obovate, 50 to 150 millimeters long, with serrated edges and rounded to heart-shaped bases, featuring leaf-like stipules with convex or rounded tips. The plant has pistillate flowers with glabrous ovaries and staminate flowers with two stamens.
Identification and appearance
Key characters: 21 sympatric species but distinctive large size, serrated leaves, and glabrous undersides
Habitat and range
Habitat: Banks of rivers, streams, marshes
Elevation: 110-2255 m
Outside California: to northern Canada, Wyoming
Bloom period
Salix prolixa blooms Mar-Jun.
How to tell it apart
vs Umbellularia: Willows have narrow leaves with no scent; crush bay laurel leaf for intense spicy aroma.; vs Baccharis: Willows have catkins; baccharis has fuzzy white seed heads and resinous stems.; vs Acacia: Willow leaves have one central vein; acacia leaves are compound with many small leaflets or modified into flat phyllodes.; vs Quercus: Willows have narrow flexible leaves; oaks have broader stiff leaves and produce acorns.; vs Schinus: Willow leaves are simple; pepper tree has compound leaves with 15-40 leaflets and peppery-scented crushed foliage.
Frequently asked questions
Is Salix prolixa native to California?
Yes. Salix prolixa is native to California (recorded as native).
When does Salix prolixa bloom?
Salix prolixa blooms Mar-Jun.
What plant family does Salix prolixa belong to?
Salix prolixa is in the Salicaceae family, genus Salix.
What habitat does Salix prolixa grow in?
Salix prolixa grows in Banks of rivers, streams, marshes.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.