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Onoclea spp.
sensitive fern
Eastern North America and eastern Asia
Overview
Onoclea spp. is a genus in the family Onocleaceae, usually treated as monotypic with the single species O. sensibilis, the sensitive fern, native to eastern North America and eastern Asia. It is a deciduous fern that spreads by long, branching rhizomes to form colonies in wet ground. The sterile fronds are broadly triangular, 30-100 cm (12-40 in) tall, deeply pinnatifid with nearly opposite, wavy-edged segments and a winged central stalk, rising singly along the rhizome on yellow-green stalks. Separate fertile fronds are shorter, erect, and woody, with the segments rolled into hard, bead-like structures that enclose the spores; these fertile fronds turn brown and stand through winter, releasing spores the following spring. The common name refers to the sterile fronds, which blacken and collapse at the first autumn frost. The fern grows in marshes, wet woods, ditches, and streamsides in sun or shade, and spreads quickly in moist, open ground, where it can crowd out smaller plants. The foliage is reported to be poisonous to horses.
Native Range
Onoclea sensibilis is native to eastern North America, from Canada south to the Gulf states, and to eastern Asia including parts of China, Korea, and Japan. It grows in marshes, wet woodland, ditches, and along streams and pond edges.Suggested Uses
Onoclea sensibilis is used in bog gardens, pond and stream margins, rain gardens, and damp shade where a spreading groundcover fern is wanted. Its rhizome-forming habit suits erosion control on wet banks but makes it too vigorous for small, mixed plantings.How to Identify
Appearance
Size & Dimensions
Height1' - 3'4"
Width/Spread2' - 4'11"
Bloom Information
As a fern, Onoclea sensibilis does not flower. Spores form inside the bead-like segments of the fertile fronds, which develop in late summer, persist over winter, and shed spores the following spring.
Detailed Descriptions
Foliage Description
yellow-greenGrowing Conditions
Sun Requirements
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight