Cystopteris fragilis
brittle bladderfern
Overview
Cystopteris fragilis is a small, delicate fern in the bladderfern family, forming tufts of finely divided fronds 4-12 inches (10-30 cm) long from a short creeping rhizome. The fronds are lance-shaped in outline and twice to three times divided into many small, toothed segments, carried on slender, brittle stalks that snap easily, the source of the common name. New fronds unfurl in spring, and in dry summer conditions the foliage often withers early before fresh fronds appear with cooler, moister weather. On the undersides of fertile segments, the spore clusters are covered by a thin, hood-like flap that gives the bladderfern its name. The fern grows on shaded, moist rock, cliff ledges, talus, mossy banks, and rich woodland soil, usually where limestone or other base-rich rock keeps the ground neutral to alkaline. It is a cosmopolitan fern, occurring across temperate, boreal, and montane regions of both the Northern and Southern Hemispheres. The plants are small and short-fronded, offering little mass, and the brittle, drought-sensitive foliage limits their use to cool, consistently moist shade.
Native Range
Cosmopolitan, occurring on shaded rock and in woodlands across temperate, boreal, and montane regions of North America, Eurasia, and beyond.Suggested Uses
Used in shaded rock gardens, on moist walls, and in woodland plantings where cool, damp conditions allow its finely cut fronds to persist. It suits crevice plantings over limestone and shaded north-facing stonework.How to Identify
Appearance
Size & Dimensions
Height4" - 1'
Width/Spread4" - 10"
Bloom Information
As a fern, Cystopteris fragilis reproduces by spores rather than flowers. Spores ripen on the frond undersides in late spring and early summer and are shed before the foliage withers.
Detailed Descriptions
Foliage Description
light green to medium 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
Grows in part shade to full shade on moist, well-drained soils rich in humus, often over limestone or other base-rich rock. It needs steady moisture and cool conditions and withers early in summer heat or drought. Soil pH from 6.0 to 8.0 suits it, reflecting its preference for neutral to alkaline ground. The fern is hardy in USDA zones 2-8 and tolerates severe winter cold. Propagation is by spores or by careful division of the rhizome in spring. In dry or sun-exposed sites it fades quickly and rarely persists.Pruning
No pruning is needed. Withered fronds can be removed as they die back, and fresh fronds replace them when cool, moist conditions return.Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons