Swamp Lousewort
Pedicularis lanceolata
Last reviewed: August 2026
Swamp lousewort is a wetland forb that blooms pale yellow flowers from June through August in wet meadows, fens, and marshy ground across the eastern and midwestern United States.
Toxicity unknown
Swamp Lousewort (Pedicularis lanceolata) 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
8"–24" H × 4"–12" W
Bloom
Jun, Jul, Aug
Native to
AR, CT, DE, GA and 21 more states
Pollinators
bees, butterflies
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Swamp lousewort is a native perennial wildflower that produces distinctive yellow, tubular flowers from June through August. This moisture-loving plant forms compact clumps with finely divided foliage and grows 8-24 inches tall. It thrives in consistently moist to wet soils and partial sun conditions.
Growing Swamp Lousewort
Grow Swamp Lousewort in part sun and high water. Mature plants reach 8 to 24 inches tall and spread 4 to 12 inches wide. Expect high maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Swamp Lousewort takes more care to keep looking intentional in a front yard. Maintenance level: high. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Requires consistently wet soil conditions that may appear unkempt
- Wild appearance doesn't fit typical landscaping expectations
- Name contains 'lousewort' which could raise concerns
Wildlife value
The tubular flowers attract bees and butterflies during the summer blooming period. This native plant provides nectar for pollinators when many other flowers may be stressed by summer heat.
Common questions
- When does swamp lousewort bloom?
- Swamp lousewort typically flowers from June through August, producing pale yellow blossoms on upright stems.
- What pollinates swamp lousewort?
- Bumblebees and other bee species are the main pollinators, and butterflies also visit the flowers for nectar.
- What growing conditions does swamp lousewort prefer?
- It grows best in consistently wet to moist soil with part sun exposure, the kind of conditions found in wet meadows, marsh edges, and fens.
- Is swamp lousewort easy to identify?
- Look for its lance-shaped, toothed leaves and dense spikes of pale yellow, hooded flowers rising above wetland vegetation in mid to late summer.
- Is Swamp Lousewort HOA-friendly?
- Swamp Lousewort 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 vouchered herbarium specimen records and regional native plant society lists. 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
These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.
- It is dying right after planting
- Leaves turning yellow
- Wilting even though I watered it
- Brown crispy leaf tips
- Bugs on the plant
Ready to grow Swamp Lousewort? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
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