Lesser Marsh St. Johnswort
Triadenum tubulosum
Last reviewed: August 2026

Toxicity unknown
Lesser Marsh St. Johnswort (Triadenum tubulosum) 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
6"–24" H × 4"–12" W
Bloom
Jun, Jul, Aug, Sep
Native to
AL, AR, FL, GA and 15 more states
Pollinators
bees, beetles
Before you buy
Your city may pay you to plant this
Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 445 programs across 44 states, each with a link to the provider and the date we last checked it.
Find rebates in your areaBrowse plants for this ecoregion
Lesser marsh St. Johnswort is a compact native perennial that thrives in consistently moist soils and partial sun conditions. It produces small yellow flowers from summer through early fall and maintains a low, bushy growth habit. This wetland plant is ideal for rain gardens, pond edges, or areas with poor drainage.
In an HOA neighborhood
Lesser Marsh 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.
- Requires consistently wet conditions that may look messy
- Unknown winter appearance could be problematic
- Small stature may appear unkempt in formal landscapes
Wildlife value
The flowers attract native bees and beetles during the long blooming season from June through September. Its presence in wet areas also supports beneficial insects that contribute to overall garden ecosystem health.
Common questions
- How much sun does Lesser Marsh St. Johnswort need?
- Lesser Marsh St. Johnswort grows best in part sun conditions.
- When does Lesser Marsh St. Johnswort bloom?
- Lesser Marsh St. Johnswort blooms in June, July, August, and September.
- Where is Lesser Marsh St. Johnswort native?
- Lesser Marsh St. Johnswort (Triadenum tubulosum) is native to AL, AR, FL, GA and 15 more states, per the World Checklist of Vascular Plants (Kew).
- What pollinators does Lesser Marsh St. Johnswort attract?
- Lesser Marsh St. Johnswort draws bees and beetles.
- Is Lesser Marsh St. Johnswort HOA-friendly?
- Lesser Marsh 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.
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 Lesser Marsh St. Johnswort? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Not sure where to start? Take the 2-minute yard quiz