Thelypteris palustris
marsh fern
Overview
Thelypteris palustris is a deciduous fern of wet meadows and marshes across the Northern Hemisphere, sending up scattered, upright fronds 1-2.5 ft (30-75 cm) tall from a slender, far-creeping rhizome rather than a tight clump. The fronds are once-divided into many narrow segments, light green and thin, on a long smooth stalk, so the colony looks loose and airy. Fertile fronds stand taller and more erect than the sterile ones, with their leaflet margins rolled under to cover the spore clusters. It spreads steadily through wet soil and can form broad stands. It grows in marshes, wet meadows, fens, swamps, and ditches in full sun to part shade with constant moisture. The creeping rhizome can travel beyond its intended area in a garden. The fronds die back at the first hard frost. It tolerates standing water and seasonal flooding.
Native Range
Native across much of North America, Europe, and Asia. In North America it ranges from Canada south through the central and eastern United States, growing in marshes, wet meadows, fens, swamp edges, and wet ditches.Suggested Uses
Grown in bog gardens, pond and stream margins, rain gardens, and wet meadow plantings for its spreading green fronds. It is planted in moist drifts spaced 18-24 in (45-60 cm) apart where it can knit wet soil. It gives cover for amphibians and other wetland wildlife.How to Identify
Appearance
Size & Dimensions
Height1' - 2'6"
Width/Spread1'6" - 3'
Reaches mature size in approximately 3 years
Bloom Information
Ferns do not flower; this species reproduces by spores. Spore clusters mature under the rolled margins of the taller fertile fronds through summer, about June to September. New fronds rise from the rhizome through spring and summer where the soil stays wet.
Detailed Descriptions
Foliage Description
light greenGrowing Conditions
Sun Requirements
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Thelypteris palustris grows in full sun to part shade in constantly moist to wet, acidic to neutral soils at a pH of 5.0-7.0 and tolerates standing water and seasonal flooding. It needs steady moisture and declines quickly if the soil dries out. It grows in mucky, peaty, or silty ground without fertilizer. The slender rhizome creeps widely, so it spreads through a bed unless contained. It dies back fully at the first hard frost and returns from the rhizome in spring. It has few pests or diseases.Pruning
Cut back dead fronds in late fall or winter after they collapse, since the fern is fully deciduous. No other pruning is needed. Sections of rhizome can be lifted in spring to control spread or to start new plants.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
fallwinter
Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons