Eriogonum giganteum var. compactum
Santa barbara island buckwheat, Santa Barbara Island Buckwheat
Photo: parent species Eriogonum giganteum · (c) Adam J. Searcy, some rights reserved (CC BY) · licence
Family: Polygonaceae · Type: Shrub · Native
Conservation status: CNPS 1B.3
Eriogonum giganteum var. compactum (Santa barbara island buckwheat) is a native California shrub in the Polygonaceae family, recognized by geographic isolation to Santa Barbara Island.
Santa barbara island buckwheat is a rare (CNPS 1B.3) California native shrub found on southern Channel Islands, specifically Santa Barbara Island, in gravel habitats at elevations below 100 meters. Flowering from May to October, this plant produces white to cream-colored flowers in compact clusters 2 to 15 centimeters wide. Growing 4 to 6 decimeters tall with densely tomentose stems 2 to 3 decimeters long, it forms a compact, robust structure. Its leaves are tomentose with blades 2.5 to 3.5 centimeters long and 1.5 to 2 centimeters wide, creating a soft, grayish-green appearance. The small flowers and fruits, measuring approximately 2 to 2.5 millimeters, contribute to its delicate yet sturdy botanical character.
Identification and appearance
Key characters: 20 sympatric species; key feature is geographic isolation to Santa Barbara Island
Habitat and range
Habitat: Gravel
Elevation: < 100 m
California counties: Santa Barbara
Bloom period
Eriogonum giganteum var. compactum blooms May-Oct.
Conservation status
CNPS 1B.3
How to tell it apart
vs Adenostoma: Eriogonum has flowers in cup-like involucres; Adenostoma has tiny white rose-family flowers in spikes.; vs Salvia: Eriogonum has six similar perianth parts; Salvia has two-lipped tubular flowers.; vs Fagopyrum: Eriogonum has flowers in involucred clusters; Fagopyrum has loose branching sprays without involucres.; vs Artemisia: Eriogonum has cup-surrounded flower clusters; Artemisia has tiny inconspicuous heads in drooping sprays.; vs Chorizanthe: Eriogonum has multiple flowers per involucre; Chorizanthe has one flower per involucre with spiny teeth.
Frequently asked questions
Is Eriogonum giganteum var. compactum native to California?
Yes. Eriogonum giganteum var. compactum is native to California (recorded as native).
When does Eriogonum giganteum var. compactum bloom?
Eriogonum giganteum var. compactum blooms May-Oct.
Where in California does Eriogonum giganteum var. compactum grow?
Eriogonum giganteum var. compactum occurs in Santa Barbara, at elevations of < 100 m.
What plant family does Eriogonum giganteum var. compactum belong to?
Eriogonum giganteum var. compactum is in the Polygonaceae family, genus Eriogonum.
Is Eriogonum giganteum var. compactum rare or endangered?
Eriogonum giganteum var. compactum carries California Rare Plant Rank 1B.3, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
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.