Hypericum hookerianum
Hooker's st. johnswort
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Family: Hypericaceae · Type: Shrub · Not Native
Hypericum hookerianum (Hooker's st. johnswort) is a non-native California shrub in the Hypericaceae family, recognized by large petiolate leaves in limited range.
Hooker's st. johnswort is a naturalized shrub found in the northern California coastal region of Mendocino County in shaded forest at an elevation of 30 meters. Flowering in July, this plant produces bright yellow flowers 15 to 30 millimeters long in small clusters of 1 to 5 blooms. Growing as an evergreen shrub with erect to spreading branches, it reaches 3 to 2.1 meters tall with many-branched stems. Its leaves are ovate to broadly lanceolate, 25 to 75 millimeters long, with glands appearing in short lines or dots across the leaf surface. The fruit is an ovoid capsule 9 to 17 millimeters long, containing tiny dark red-brown seeds.
Identification and appearance
Key characters: 3 sympatric species; diagnostic large petiolate leaves in limited range
Habitat and range
Habitat: Shaded forest
Elevation: 30 m
Outside California: native to southern Asia
Bloom period
Hypericum hookerianum blooms Jul.
How to tell it apart
vs Euphorbia: Euphorbia has milky sap and tiny flowers in cups; Hypericum has clear sap and showy yellow flowers.; vs Lysimachia: Lysimachia has stamens separate, not bundled; Hypericum's stamens cluster into 3-5 distinct bunches.; vs Lonicera: Lonicera is a woody vine or shrub; Hypericum is herbaceous with opposite leaves.; vs Dendromecon: Dendromecon is a woody shrub with 4 petals; Hypericum is herbaceous with 5 petals.; vs Mentzelia: Mentzelia has rough, sandpapery leaves; Hypericum has smooth leaves with translucent dots.
Frequently asked questions
Is Hypericum hookerianum native to California?
No. Hypericum hookerianum is not native to California (recorded as not native).
When does Hypericum hookerianum bloom?
Hypericum hookerianum blooms Jul.
What plant family does Hypericum hookerianum belong to?
Hypericum hookerianum is in the Hypericaceae family, genus Hypericum.
What habitat does Hypericum hookerianum grow in?
Hypericum hookerianum grows in Shaded forest.
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.