Brittle Bladder Fern
Cystopteris fragilis
Family: Dryopteridaceae
What it is like
Cystopteris fragilis is a deciduous Fern growing to 0.2 m (0ft 8in) by 0.2 m (0ft 8in). See above for USDA hardiness. It is hardy to UK zone 2. The seeds ripen from July to August. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It prefers moist soil.
Height (m): 0.2
Where it is found
Rocky woods, shady rocks and walls, especially on basic rocks, to 1200 metres.
Cosmopolitan, found in most areas of the world, including Britain, but only on mountains in Tropics.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 1
Root. An emergency food, it is only used when all else fails.
Root: includes bulbs, corms, tubers, rhizomes etc.
Medicine
Rating: 1
A decoction of the roots has been used as an anthelmintic enema. A cold compound infusion of the plant has been used both internally and externally as a treatment for injury.
Anthelmintic: Expels parasites from the gut.
Other
Rating:
Plants can be grown as a ground cover when planted out about 15cm apart each way.
Ground cover: Ground Cover
How it is grown
Prefers a shady position in a moist but well-drained soil, succeeding in most soil types. Plants can tolerate up to 4 hours direct sun per day. Prefers a pH between 6.5 and 7, but tolerates a range from 5.5 to 7.5. Plants do especially well when grown in a shaded position on old mortared walls. Members of this genus are rarely if ever troubled by browsing deer. Plants die back early in dry seasons. A very ornamental plant.
Propagating it: Spores - best sown as soon as ripe on the surface of a humus-rich sterilized soil. Keep the compost moist, preferably by putting a plastic bag over the pot. Germinates in 1 - 3 months at 20°c.Pot on small clumps of plantlets as soon as they are large enough to handle and keep humid until they are well established. Do not plant outside until the ferns are at least 2 years old. Division in spring.
Best place to grow: Woodland Garden Dappled Shade; Shady Edge; not Deep Shade; Ground Cover; North Wall. In. East Wall. In.
Habit: Fern
Hardiness: 0-0
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: Full shade, semi-shade
Moisture: Moist
Things to keep in mind
Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable. Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase.