Narthecium ossifragum
bog asphodel
Overview
Narthecium ossifragum is a creeping perennial of acid bogs, 4-16 inches (10-40 cm) tall, spreading by a slender rhizome through wet peat. The flattened, iris-like leaves are 2-12 inches (5-30 cm) long, held in two ranks, ribbed, and curved like a sickle. In mid to late summer leafless stems carry a spike of star-shaped flowers, each with six narrow yellow tepals about 0.3 inch (8 mm) long and woolly orange stamens. After flowering the whole spike turns deep orange then rusty-brown, holding colour well into autumn as the seed capsules ripen. It grows only where the ground stays wet and acidic, such as blanket bog, wet heath, and flushed moorland, and disappears from drained or limed land. The plant contains saponins, and grazing it can cause photosensitisation and kidney damage in sheep, a disorder known as alveld. The old name ossifragum, meaning bone-breaker, came from a belief that it weakened the bones of stock, in fact a result of the calcium-poor bog soils. It is slow to establish and does not tolerate drying out.
Native Range
Narthecium ossifragum is native to western Europe, from Scandinavia and the British Isles south to Portugal. It grows in acidic, permanently wet peatlands, including blanket bog, valley mire, and wet heath.Suggested Uses
Grown in bog gardens, acid pond and stream margins, and peat beds where the soil stays wet year round. Suited to naturalistic moorland and wetland plantings on lime-free ground.How to Identify
Appearance
Size & Dimensions
Height4" - 1'4"
Width/Spread6" - 1'
Bloom Information
Yellow star flowers open from July to August up a short spike, the lower flowers opening first. As bloom fades the stems and capsules flush orange and brown, a colour that lasts through autumn. Flies and small bees visit the open flowers.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow only in permanently moist to wet, acidic, lime-free soil such as peat or a peat-sand mix, in full sun to light shade. It suits the margins of bog gardens and acid pond edges where the roots never dry out. Standing water or saturated peat through the year matches its needs, while any drying or liming kills it. No feeding is needed, as it is adapted to nutrient-poor ground. It spreads slowly by rhizome and is slow to recover from disturbance once settled. Container culture works only with an acidic, water-retentive mix kept constantly wet.Pruning
No pruning is required. Spent flower stems are left in place, as the orange seed heads carry interest into autumn and shed seed naturally. Old foliage dies back to the rhizome over winter.Container Growing
✓ Suitable for container growing
Minimum container size: 2 gallons