Dryopteris expansa aka Northern Buckler Fern

Dryopteris expansa is a perennial fern known as spreading woodfern or spiny wood fern. Its native range spans the subarctic and temperate Northern Hemisphere. It grows across Europe, northern North America, and parts of Asia. It is native to Britain and Ireland. In the wild, it grows in cool, damp woods. It often takes root on decaying logs and old stumps.

Plants reach about 1.3 feet (0.4 metres) tall and 1.6 feet (0.5 metres) wide. This modest size suits small woodland beds and shaded borders. The plant has underground rhizomes and produces young shoots in spring. It is closely related to Dryopteris dilatata. Where their ranges overlap, the two can form the hybrid Dryopteris × ambroseae. Growers can raise new plants from spores or divide established clumps.

This fern grows well in moist, fertile garden soil. It accepts sand, loam, and clay, with an acid to neutral pH. PFAF describes it as easy to grow in shade. Its shade guidance varies between sections of the same account. One section allows deep shade, while another favours dappled shade and woodland edges. A moist site with light woodland shade fits both its habitat and garden use. PFAF lists USDA zones 3–7 for hardiness.

Sow spores on the surface of sterile compost and keep them moist. PFAF gives a germination time of one to three months at 68°F (20°C). Grow small clumps in a shaded greenhouse until large enough to plant outside. Divide plants in spring. Large divisions can go straight into their final site. Keep small divisions in pots under cover until they root well. These methods offer two ways to build a woodland planting.

PFAF records food uses for the roots and young shoots. Cooking makes the bitter roots sweeter; people have also added cooked shoots to soups. These records do not establish that the plant is safe to eat. The fresh plant contains thiaminase, which can reduce the body's supply of vitamin B1. Heat or thorough drying destroys this enzyme. PFAF still urges caution about eating ferns. It records pounded roots applied to cuts and leaves used in hair washes. These are historical uses, not proof of safety or benefit.