Telmatoblechnum serrulatum
toothed midsorus fern
Southeastern US, Caribbean, and tropical America
Overview
Telmatoblechnum serrulatum is an evergreen fern with pinnate fronds 2-4 feet (60-120 cm) long, rising from a creeping, branching rhizome that forms spreading colonies. Each frond is divided into many narrow, leathery leaflets 2-4 inches (5-10 cm) long with finely toothed (serrulate) margins. New fronds emerge pink to coppery red before turning deep green. Spore-bearing sori form in continuous lines along both sides of the leaflet midrib, on the undersides of fertile fronds. The rhizome creeps at or just below the surface, sending up fronds at intervals to build dense stands in wet ground. It grows in standing water and saturated soil and spreads steadily where conditions stay wet. In drier soil the fronds brown at the tips and the colony thins.
Native Range
Native to the Americas from the southeastern United States, including Florida, through the Caribbean and Central America to tropical South America, with related populations in the Old World tropics. Grows in freshwater marshes, wet prairies, swamp margins, ditches, and wet pine flatwoods in full sun to part shade.Suggested Uses
Planted at pond and stream margins, in bog gardens, and in rain gardens on permanently wet ground, spaced 18-24 inches (45-60 cm) apart for a solid stand. Its spreading rhizome suits naturalized wet areas more than confined beds, where it can crowd neighbors. Grows in containers standing in water or in consistently wet potting mix.How to Identify
Appearance
Size & Dimensions
Height2' - 4'
Width/Spread2' - 4'
Bloom Information
Ferns do not flower. Spores ripen on the undersides of fertile fronds through the warm months and are released to establish new plants in wet ground. Most spread in cultivation and in the wild comes from the creeping rhizome rather than from spores.
Detailed Descriptions
Foliage Description
green, emerging pink to redGrowing Conditions
Sun Requirements
Requires 4-10 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
Grows in wet to saturated soil or shallow standing water in full sun to part shade. Keep the soil constantly wet; the fern browns and declines if it dries out. It spreads by creeping rhizomes and can fill a wet bed or pond edge within a few seasons. The plant needs little feeding in mucky, organic soils. Few pests trouble it, though scale insects appear on fronds in some settings. Old or damaged fronds can be cut away at any time.Pruning
Cut away browned or storm-damaged fronds at the base as needed; the rhizome produces fresh fronds through the season. To limit spread, cut back or divide the creeping rhizome at the edges of the stand. No seasonal pruning is required in frost-free areas.Container Growing
✓ Suitable for container growing
Minimum container size: 2 gallons