Southern Marsh St. John's-wort
Triadenum tubulosum
In the Carolinas and Georgia, found in bogs, peaty wetlands, drawdown sloughs along rivers, drawdown shorelines along man-made reservoirs. Weakley, Flora of the Southeastern United States (2025), Carolinas & Georgia edition What its natural habitat tells you
Native to Louisiana. How scores work Is it native here?
Profile 88%
- Height
- Up to about 32 inches
- Light
- Partial shade, Full shade, Full sun
- Soil moisture
- Moist to wet
No photograph yet. Looking for an old drawing…
At a glance
- Life cycle
- Perennial
- Bloom
- August to September
Not yet recorded · Spread · Leaves
Recorded in 21 Louisiana parishes.
Natural habitats
Places it grows wild. Not a planting requirement. Each habitat page lists the plants and wildlife also found there.
Streams, rivers and their banks
Flowing water and its banks, bars and rocky shoals.
Still water and its edges: ponds, lakes, millponds and reservoirs.
Also found with this plant
Wildlife whose habitat models include habitats this plant grows in, in Louisiana. Shared habitat, not food. 132 animals.
- Mottled DuckAnas fulvigula
- Northern Saw-whet OwlAegolius acadicus
- Orchard OrioleIcterus spurius
- Purple GallinulePorphyrio martinica
- Red-shouldered HawkButeo lineatus
- Seaside SparrowAmmodramus maritimus
- Summer TanagerPiranga rubra
- Swallow-tailed KiteElanoides forficatus
- VeeryCatharus fuscescens
- White-crowned SparrowZonotrichia leucophrys
- Willow FlycatcherEmpidonax traillii
- Wilson's PloverCharadrius wilsonia
Widespread birds also seen here (17)
Found in many habitats here, so not listed above.
Who uses this plant?
14CaterpillarsGenus host records with ranges including LA
Genus host records with ranges including LA · Hypericum
- Acleris maculidorsanaStained-Back Leafroller Moth
- Choristoneura rosaceanaOblique-Banded Leafroller Moth, Rosaceous Leaf Roller
- Eupithecia miserulataCommon Eupithacia, Common Pug
- Iodopepla u-albumBurgundy St. Johnswort Moth, White-Eyed Borer
- Iridopsis ephyrariaPale-Winged Gray
- Mocis latipesSmall Mocis, Striped Grass Looper
- Nedra ramosulaGray Half-Spot
- Nemoria bistriariaTwo-Striped Emerald, Red-Fringed Emerald
- Platynota flavedanaBlack-Shaded Platynota
- Probole amicariaFriendly Probole
Show all 14
- Sparganothis sulfureanaSparganothis Fruitworm Moth, Sulfur Leafroller, False Yellow-Head
- Tallula watsoniWatson's Tallula
- Zale lunataLunate Zale
- Xenotemna pallorana
43BeesSoutheastern regional records
Southeastern regional records · Hypericum
Individual names are not available yet.
Noori, Seltmann & Orr 2026, A curated and integrated dataset for exploring global bee-plant interactions (GloBI), Zenodo, CC BY 4.0
1BirdsRecorded eating Triadenum in Louisiana
Diet records by plant genus, from studies across North America. Not a record from this state. Birds whose range includes Louisiana, most records first.
- Wood DuckSeeds. 1 diet record
Direct food only. Caterpillars on host plants also feed nesting birds. NC Native Plant Society: butterfly gardening
No records yet · Ants · Beetles · Flies · Adult butterflies / moths · Other wasps · Other insects
Birds that eat Triadenum 1
Diet records by plant genus, from studies across North America. Not a record from this state. Avian Diet Database (Hurlbert Lab), CC0 1.0.
- Wood DuckAix sponsa
Plant details
- Family
- Hypericaceae
- Flower color
- Pink
Safety has not been reviewed for this plant; check toxicity and thorns before planting.
Growing sources and scope
- Bloom · “August to September” · Weakley, Flora of the Southeastern United States (2025), Carolinas & Georgia edition · Carolinas and Georgia
- Flower color · “Pink” · Lady Bird Johnson Wildflower Center
- Height · “Up to about 32 inches” · Lady Bird Johnson Wildflower Center
- Life cycle · “Perennial” · Lady Bird Johnson Wildflower Center
- Light · “Partial shade; Full shade; Full sun (documented habitat)” · Weakley, Flora of the Southeastern United States (2025), Carolinas & Georgia edition · Carolinas and Georgia
- primary_flower_color · “pink” · Lady Bird Johnson Wildflower Center
- Soil · “Moist; Wet (documented habitat)” · Weakley, Flora of the Southeastern United States (2025), Carolinas & Georgia edition · Carolinas and Georgia
Also known as
Hypericum tubulosum; Lesser Marsh St. Johnswort; Southern Marsh St. John's wort; john's wort; john's-wort
Conservation status
| Louisiana rank | SNR |
|---|---|
| Global rank | G4? |
| LA status | Not verified |
| Federal status | Not verified |
Will it fit your yard?
Check this plant against your county, sun and soil moisture. Conditions are checked in your browser.
Sources
- Weakley, Flora of the Southeastern United States (2025), South Central edition
- USDA PLANTS
- Vascular Plants of North Carolina (NC Natural Heritage Program)
- Louisiana occurrence source
- Shropshire & Tallamy 2025, Lepidoptera of North America north of Mexico, ZooKeys 1261 (ODbL)
- Noori, Seltmann & Orr 2026, A curated and integrated dataset for exploring global bee-plant interactions (GloBI), Zenodo, CC BY 4.0
- Smith, Bachelder, Russell, Morales, Mosher & Seltmann 2024, Bee-Specialization-Modeling v0.6.1 (specialist host table compiled from J. Fowler's pollen specialist bee lists), Zenodo, CC BY 4.0
- Hurlbert, Olsen, Sawyer & Winner 2021, Avian Diet Database, Scientific Data 8: 260 (CC0)
- Narango, Tallamy & Shropshire 2020, Few keystone plant genera support the majority of Lepidoptera species, Nature Communications













