Cystopteris protrusa
lowland brittle fern
Overview
Cystopteris protrusa is a small, delicate, deciduous woodland fern of the family Cystopteridaceae native to rich, moist forests, ravines, and shaded slopes of the eastern and central United States. It grows 8-16 inches (20-40 cm) tall from a creeping rhizome whose tip protrudes beyond the current fronds, a feature that gives the species its name and lets it form loose, spreading colonies. The light green, lance-shaped blades are twice-pinnate and finely cut, carried on brittle, easily snapped stalks. New fronds emerge early in spring, among the first ferns to appear, and the plant often goes summer-dormant in dry conditions, dying back by late season. Spore cases sit beneath the segments under a thin, hood-like cover that shrivels as the spores ripen in late spring and summer. It needs cool, moist, humus-rich shade and tends to disappear in hot, dry, or sunny sites, returning from its rhizome the next spring. In cultivation it is used as an early-season groundcover in woodland and shade gardens and along shaded paths and stream banks.
Native Range
Native to the eastern and central United States, from the Great Lakes and New England south to Georgia and west to Texas and the Great Plains. It grows in rich, moist deciduous woods, on shaded slopes, in ravines, and along stream banks.Suggested Uses
Used as an early-season groundcover in woodland and shade gardens, along shaded paths, and on stream banks and slopes. It suits naturalistic shaded plantings that allow for its summer dormancy.How to Identify
Appearance
Size & Dimensions
Height8" - 1'4"
Width/Spread1' - 2'
Colors
Foliage Colors
Bloom Information
As a fern, it produces no flowers and reproduces by spores. Spore cases under thin, hood-like covers ripen in late spring and summer. The fern often goes dormant by midsummer in dry conditions.
Detailed Descriptions
Foliage Description
light greenGrowing Conditions
Sun Requirements
Tolerates up to 4 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
Grow in part to full shade in cool, moist, humus-rich, well-drained soil. The species needs steady moisture in spring and tolerates summer dryness by going dormant, reappearing from its rhizome the following year. Hot, dry, or sunny sites cause the fronds to brown and collapse early. Work leaf mold or compost into the soil and keep a shaded, leaf-littered surface. It spreads slowly into loose colonies and needs no fertilizer. The brittle fronds break easily, so it is placed away from heavy foot traffic. Hardy in USDA zones 4-8.Pruning
No pruning is needed. Spent or dormant fronds can be cleared once they wither, or left as leaf litter. The fern dies back on its own and returns from the rhizome in early spring.Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons