Thelypteris confluens
Common Name: marsh fern 
Type: Fern
Family: Thelypteridaceae
Native Range: Tropical Africa, tropical Asia
Zone: 3 to 8
Height: 1.50 to 2.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: Non-flowering
Bloom Description: Non-flowering
Sun: Part shade to full shade
Water: Medium to wet
Maintenance: Low
Suggested Use: Naturalize, Rain Garden
Tolerate: Heavy Shade, Wet Soil

Culture

Easily grown in moist to wet soils in full sun to part shade to full shade. Tolerates full sun if soils are kept consistently moist. Prefers fertile, moist, humusy loams that are rich in organic matter. Soils should not be allowed to dry out. Avoid standing water. Site in locations protected from strong winds to prevent damage to the fronds. The old fronds should be cut off in late winter prior to the emergence of the new growth. Propagate by division or spores. Spreads by rhizomes to form colonies.

Noteworthy Characteristics

Thelypteris confluens, commonly called marsh fern, is a deciduous fern that is native to rich muddy soils in open woodlands, marshes, bogs, wet meadows, and along ditches and streams in Canada (Newfoundland to Manitoba) and the eastern and central U.S. (Maine to South Dakota south to Florida and Texas). It is also native to Eurasia.

Marsh fern typically grows to 18-24” tall featuring upright compound leaves (fronds) with pinnate-pinnatifid blades to 18” long and 6” wide. Fertile leaves typically have longer stalks than sterile leaves. Each compound leaf has 10-40 pairs of deeply lobed leaflets. Forked veins extend to the edge of each lobe. Rounded sori (spore-producing structures) develop on the lower surface of fertile leaflet lobes, with each lobe (to 3/4” long) having significantly downturned margins (involute). Immature sori have true indusia (thin protective covers) which usually wither as the sori mature. Spores are produced in summer/fall.

Genus name comes from the Greek words thelys meaning female and pteris meaning fern.

Problems

No serious insect or disease problems.

Uses

Excellent fern for woodland or shade gardens. Containers, borders, rock gardens. Grow along shaded walls or buildings. Mass in shaded areas.