Onoclea sensibilis
sensitive fern
Overview
Onoclea sensibilis is a deciduous fern native to eastern North America and East Asia, spreading by creeping rhizomes to form colonies in wet ground. It grows 1-4 feet (30-120 cm) tall and produces two kinds of fronds. The sterile fronds are broad and nearly triangular, 8-24 inches (20-60 cm) long, with paired, wavy-edged leaflets and a pale green color, held singly along the rhizome rather than in a tight crown. The separate fertile fronds are shorter and stiff, with the leaf tissue rolled into hard, bead-like green segments that turn dark brown and persist upright through winter, releasing spores the following spring. The common name refers to the way the sterile fronds blacken and collapse at the first autumn frost. It grows in full sun to shade in consistently moist to wet soil along streams, marshes, ditches, and low woodland, spreading steadily once established. In drier ground the fronds scorch and the plant declines. The rhizomes form dense mats that can crowd nearby plants. The foliage is toxic to horses if grazed in quantity, though it is not a concern for most other animals.
Native Range
Onoclea sensibilis is native to eastern North America, from Canada through the eastern United States, and to temperate East Asia. It grows in wet meadows, marshes, streambanks, and low woodland.Suggested Uses
Onoclea sensibilis is planted along ponds and streams, in rain gardens, and in moist woodland plantings where its spreading habit fills wet ground. The upright brown fertile fronds hold through winter and add structure to the dormant garden. Its rhizomatous spread suits naturalized, damp areas rather than confined beds.How to Identify
Appearance
Size & Dimensions
Height1' - 4'
Width/Spread1' - 3'
Bloom Information
As a fern, this species does not flower; it reproduces by spores rather than seed. The fertile fronds form in summer and ripen to hard brown bead-like structures that persist upright through winter, releasing spores in early spring. The sterile, leafy fronds carry on photosynthesis through the growing season.
Detailed Descriptions
Foliage Description
pale greenGrowing Conditions
Sun Requirements
Requires 2-8 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
Onoclea sensibilis grows in full sun to full shade in consistently moist to wet, slightly acidic soils and tolerates standing water and heavy clay. It needs steady moisture and scorches in dry ground, so it suits pond edges, rain gardens, and low spots. Once established it spreads by rhizomes to form colonies, filling in wet ground over a few seasons. It needs no fertilizing and little care where moisture is reliable. The fronds die back at the first frost and return from the rhizome in spring. In garden beds its spreading roots may need a barrier to limit its reach.Pruning
The blackened fronds can be cut back after the first hard frost or left to break down over winter. The persistent fertile fronds may be removed in spring once they have shed their spores. No other pruning is needed for this fern.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
fallearly spring
Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons