The southern fragile fern is a short, rhizomatous, herbaceous perennial fern in the spleenwort family (Aspleniaceae). The name of the genus comes from the Greek words kystis, meaning “bladder,” and pteris, a fern. The name highlights the indusium, which is inflated when young. The specific epithet, protrusa , refers to the fact that the rhizome extends a short distance (less than 2 inches) beyond the latest frond. The fern grows well in dappled sun to deep shade. It does best with soil high in organic content, a neutral pH soil and good drainage. It grows 0.5 to 1.5 feet high and wide. This easy-to-grow fern is an NC native found in the mountains and piedmont regions of the state. Interestingly, it is the only species in the genus that grows on the forest floor rather than on rocks or cliffs. The fronds appear in the spring and have central stems (stipes) that break easily, hence the common name. They often turn brown and begin to disappear by mid-summer. The frond structure is bipinnate-pinnatifid to pinnate-bipinnatid with the leaflets becoming less differentiated toward the tip of the leaf blade. The sori are circular and partially covered by a bladder-shaped indusium. They turn dark brown to black as the spores mature in late spring to mid-summer. The Southern Fragile Fern can be grown in native and shade gardens and as a border feature. Insects, Diseases, and Other Plant Problems: No serious insect or disease problems. VIDEO Created by NC State Extension's Homegrown series featuring Mark Weathington , Director of JC Raulston Arboretum .
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Dappled Sunlight (Shade through upper canopy all day) | Deep shade (Less than 2 hours to no direct sunlight) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
High Organic Matter
Soil pH
Neutral (6.0-8.0)
Soil drainage
Good Drainage
Available space
Less than 12 inches; 12 inches-3 feet
NC region
Mountains; Piedmont
Mature size
Height: 0 ft. 6 in. - 1 ft. 6 in. | Width: 0 ft. 6 in. - 1 ft. 6 in.