Family: Hypericaceae

Scientific Name: Hypericum kalmainum

Common Name: Kalm St Johnswort

DescriptionA native shrub with bright yellow flowers. Tolerates moist to wet soil.
Plant TypeShrubs Deciduous
Hardiness Zone4-7
Moistureaveage, moist to wet
Soil & Siteaverage, moist to wet
Flowersbright yellow, 5 petals, 5 light green/yellow sepals, mass of yellow stamens in the center, borne in cymes
Fruit5-celled seed capsules
Leavesgreen, narrow, mostly sessil
Stemsyellowish brown to reddish brown bark, exfoliates, 4-angled
Rootsshallow spreading
Dimensionsup to 3 by 3 feet
Native Siteendemic to the Great Lake region, USA
Misc Facts"Genus name honors Peter Kalm, a student of Linnaeus, who reportedly discovered the species plant in the wild in North America in the mid-1700s". (#144)
Notes & Reference#01-Manual of Woody Landscape Plants (Michael Dirr), #144-Missouri Botanical Gardens web site (, #153-Illinois Wild Flower (
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