Polystichum luctuosum aka Korean Rockfern

Polystichum luctuosum is a small fern known as dwarf holly fern. Other names include Korean rock fern and mourning shield fern. Its range spans southern Africa and western Indian Ocean islands. In Asia, it grows from northern Pakistan to Japan and Vietnam. It lives on forest floors and rocks in evergreen woods. These sites lie about 2,500–5,700 feet [762–1,737 metres] above sea level.

This slow-growing perennial forms a low mound from rhizomes. Garden plants reach 1–1.5 feet [0.30–0.46 metres] tall and wide. The fronds arch and remain evergreen or partly evergreen. Their glossy, leathery blades have a blue-green cast and black veins. Each lance-shaped blade divides twice into smaller leaflets. Blades reach 1.5 feet [0.46 metres] long and 0.5 feet [0.15 metres] wide. Each has 12–15 pairs of narrow side divisions, called pinnae. The small leaflets have cut edges that end in bristles. Larger leaflets stand apart near the base of each pinna. Pale brown frond axes carry black scales. The leaf stalks bear dark scales on pale to medium brown stems.

This fern makes neither flowers nor fruit. It reproduces through spores rather than seeds. Round spore clusters, called sori, measure about one millimetre across. A round, dark brown membrane covers each cluster. Gardeners can raise new plants from spores or divide the rhizomes. Its fine leaf divisions give the plant a light texture. The dark veins stand out against the glossy blades.

Grow it in part shade or full shade. It also tolerates deep shade beneath other plants. Give it moist soil rich in humus, with good drainage. It accepts clay, loam, and sand when drainage is sound. It also grows in acid, neutral, or alkaline soils. Sources place its hardiness in USDA zones 6–9. Its water needs are moderate, and upkeep is low. Remove dead or damaged fronds when needed. Excess water and poor drainage can cause crown rot. Winter wet raises this risk. Sources report no major insect or disease problems. Deer and rabbits tend to leave it alone.

Its small size suits rock gardens, woodland beds, and shaded borders. Plant groups can form ground cover beneath large shrubs. It also suits cottage gardens and pots, including indoor containers. The lasting fronds add interest through winter. Its foliage has also served the floral trade in boutonnieres. The supplied sources give no food uses or toxicity assessment.