Botrychium lunaria aka Common Moonwort

Botrychium lunaria, or common moonwort, is a small perennial fern. It belongs to the Ophioglossaceae family. Its native range includes Greenland and temperate and subarctic Old World regions. It grows wild in Britain and Ireland. In Britain, it occurs mainly in the north and west. Other names include grape fern, lunary, and moon fern.

This fern has an upright form and sheds its foliage. It makes one yellow-green frond with a firm, leathery feel. The frond reaches about 0.66 feet [0.2 metres] long. Its fan-shaped lobes give the leaf a clear shape. In summer, a branching spike carries small, round, brown sporangia. These structures hold spores, which growers can use for propagation. The summer spike is a spore-bearing structure, not a flower. Its small size suits places where larger plants would dominate.

Wild plants grow in grassland, dunes, and on rock ledges. They also occur on slag heaps and other fairly dry sites. Plants For A Future also records plants on peaty soils. In gardens, the RHS recommends partial shade and good drainage. Clay, loam, and sand can all suit it. Soil may be acid, neutral, or alkaline. Moisture can range from dry to moist, provided water drains well. A sheltered site suits its listed growing needs. North-, east-, and west-facing sites fit the RHS guidance.

The RHS gives moonwort a UK hardiness rating of H5. This covers minimum temperatures from about −15 to −10°C. It lists a maturity period of two to five years. Suggested settings include rock gardens, wildflower meadows, and wildlife gardens. Banks and slopes are also listed as suitable planting sites. Its small frond and summer spore spike provide the main interest. It needs no pruning. The RHS reports few usual problems with pests or disease.

Plants For A Future lists no known edible uses. It also records no known hazards, but this does not prove safety. The same source describes past medicinal use of the leaves. People used them in ointments and took them internally. Reported uses include wounds, ruptures, and dysentery. These historical records do not establish safe or effective treatment. No other uses are recorded, and the source does not class it as weedy.