How much sun does Fraser's marsh St. John's wort need?

Fraser's marsh St. John's wort grows best in part sun conditions.

When does Fraser's marsh St. John's wort bloom?

Fraser's marsh St. John's wort blooms in July, August, and September.

Where is Fraser's marsh St. John's wort native?

Fraser's marsh St. John's wort (Triadenum fraseri) is native to CT, DE, IA, IL and 21 more states, per the World Checklist of Vascular Plants (Kew).

What pollinators does Fraser's marsh St. John's wort attract?

Fraser's marsh St. John's wort draws bees.

Fraser's marsh St. John's wort

Name: Pollinator Patch
Author: Pollinator Patch

Triadenum fraseri

Last reviewed: November 2026

Fraser's marsh St. John's wort (Triadenum fraseri) is a perennial forb native to CT, DE, IA, IL and 21 more states. It blooms in July, August, and September. The flowers draw bees.

Watering reminders and freeze alerts for Fraser's marsh St. John's wort, free in the app.

Toxicity unknown

Fraser's marsh St. John's wort (Triadenum fraseri) 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

part sun

Water

high

Size

12"–24" H × 8"–12" W

Bloom

Jul, Aug, Sep

Native to

CT, DE, IA, IL and 21 more states

Pollinators

bees

Before you buy

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Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 461 programs across 44 states, each with a link to the provider and the date we last checked it.

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An upright perennial with paired, oval leaves and small pink flowers that open only briefly in sunshine, growing in saturated soils of bogs and wet meadows. It holds an upright, slender form in standing water.

Growing Fraser's marsh St. John's wort

Grow Fraser's marsh St. John's wort in part sun and high water. Mature plants reach 12 to 24 inches tall and spread 8 to 12 inches wide.

Wildlife value

Flowers are worked by native bees during their brief daily opening, and dense bog stands provide cover for wetland insects.

Common questions

How much sun does Fraser's marsh St. John's wort need?: Fraser's marsh St. John's wort grows best in part sun conditions.
When does Fraser's marsh St. John's wort bloom?: Fraser's marsh St. John's wort blooms in July, August, and September.
Where is Fraser's marsh St. John's wort native?: Fraser's marsh St. John's wort (Triadenum fraseri) is native to CT, DE, IA, IL and 21 more states, per the World Checklist of Vascular Plants (Kew).
What pollinators does Fraser's marsh St. John's wort attract?: Fraser's marsh St. John's wort draws bees.

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

If something looks wrong

Common plant problems, and what to check first

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Ready to grow Fraser's marsh St. John's wort? Add it to your garden in the Pollinator Patch App to track it and get season-by-season care guidance.

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