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Large St. Johnswort

Hypericum majus

Last reviewed: August 2026

Hypericum majus (Large St. Johnswort) is a native forb blooming yellow flowers from June through September across northern and western US states. This adaptable wildflower attracts bees and beetles in full sun conditions.

Large St. Johnswort (Hypericum majus)
Photo: aarongunnar https://www.inaturalist.org/people/aarongunnar / Wikimedia Commons (CC BY 4.0)

Toxicity unknown

Large St. Johnswort (Hypericum majus) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.

Light

full sun

Water

medium

Size

4"–12" H × 2"–6" W

Bloom

Jun, Jul, Aug, Sep

Native to

CO, CT, IA, ID and 23 more states

Pollinators

bees, beetles

Before you buy

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Large St. Johnswort is a low-growing annual wildflower that produces small yellow blooms from summer through early fall. This compact native forb stays under a foot tall and spreads modestly, making it suitable for naturalized areas and wildlife gardens.

Growing Large St. Johnswort

Grow Large St. Johnswort in full sun and medium water. Mature plants reach 4 to 12 inches tall and spread 2 to 6 inches wide. Expect low maintenance to keep it looking intentional in a front yard.

In an HOA neighborhood

Large St. Johnswort takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.

Works well in: backyard only.

  • Annual growth means gaps and bare spots
  • Wild appearance doesn't fit formal landscaping
  • May be perceived as weedy by neighbors

Wildlife value

The bright yellow flowers attract native bees and beetles during its long blooming period from June through September.

Common questions

When does Hypericum majus bloom?
Large St. Johnswort blooms from June through September, producing bright yellow flowers throughout the summer months.
What pollinators visit Large St. Johnswort?
Bees and beetles are the primary pollinators attracted to Hypericum majus flowers.
Where is Hypericum majus native?
Large St. Johnswort is native to 28 US states, primarily across the northern tier from Maine to Washington and extending south through the Great Plains and some mid-Atlantic states.
What growing conditions does Large St. Johnswort prefer?
This species thrives in full sun with medium moisture levels but can adapt to various light and water conditions.
Is Large St. Johnswort HOA-friendly?
Large St. Johnswort takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.

Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

Ready to grow Large St. Johnswort? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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