Dryopteris cristata aka Crested Buckler Fern

Dryopteris cristata is known as crested wood fern or narrow swamp fern. This perennial fern grows across the temperate Northern Hemisphere. Its native range spans Europe to central Siberia, plus Canada and the United States. It is also native to Britain and Ireland. Wild plants grow in damp woods, swamps, and shrubby wetlands. In North Carolina, it occurs in cool regions.

The plant forms clumps and spreads through creeping rhizomes. Garden size varies between sources. RHS gives heights of 0.3–1.6 feet [0.1–0.5 metres]. NC State gives 1–3 feet [0.3–0.9 metres]. RHS lists a spread of 1.6–3.3 feet [0.5–1 metre]. NC State allows a wider spread, reaching 6 feet [1.8 metres]. Growth is moderate, and plants take two to five years to mature. Its narrow fronds give the clump an upright shape.

The dark green, leathery fronds have two distinct forms. Taller fertile fronds stand upright and die back in winter. Shorter sterile fronds arch outward and stay green. Fronds reach 2.5 feet [0.76 metres] long. Each frond divides once into leaflets and narrows toward its tip. The lower leaflets are larger and triangular. Upper leaflets have lobes with bristle-tipped teeth. On fertile fronds, these leaflets turn to lie flat. Green stems bear scattered tan scales, with more near the base. This fern makes neither flowers nor fruit. Brown sori sit beneath fertile fronds and hold the spores.

Grow it in partial shade with moist, humus-rich soil. It also tolerates deep shade. Acid to neutral soil suits it best. NC State records tolerance of wet soil and standing water. RHS instead advises moist soil without waterlogging. It grows in loam, while RHS also lists clay. Its hardiness ratings are USDA zones 3–7 and RHS H6. Plants need little upkeep and no pruning. Divide clumps or raise new plants from spores.

Use it beneath shrubs, in borders, or in woodland gardens. It also suits rain gardens and stream or pond margins. The lasting sterile fronds add winter interest. Deer seldom damage it, and sources report few pest or disease problems. PFAF lists no known food uses. It warns that the fresh plant contains thiaminase. Large amounts can cause serious health problems through vitamin B loss. NC State records past medicinal use, but gives no treatment guidance.