interrupted fern
Osmunda claytoniana · Osmundaceae
interrupted fern (Osmunda claytoniana) is a perennial herbaceous plant in the Osmundaceae family. It is native to North America. USDA records it as hardy in zone 3 and warmer, down to about -38°F.
At a glance
| Type | forb-herb USDA |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 4 ft USDA |
| Light | shade USDA |
| Water need | high USDA |
| Growth rate | moderate USDA |
| Soil pH | 4–6 USDA |
| Bloom | July USDA |
| Flower color | Brown USDA |
| Hardiness zones | 3 and warmer USDA |
| Guild layer | herb-layer Derived |
| Nursery availability | Routinely Available USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It tolerates full shade. USDA rates it as having needs consistently moist ground. Its drought tolerance is rated low. It handles periodically wet ground (USDA rates its anaerobic tolerance medium). It is recorded on soils from pH 4 to 6 — acidic ground. Its cold limit is zone 3.
Size and growth
At maturity it reaches about 4 ft, making it roughly waist to chest height. It grows at a moderate rate.
Bloom period
USDA records a bloom period of July. Flowers are brown.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is dark green, medium in texture. Its flowers are not conspicuous — a plant for form and foliage. It carries conspicuous autumn colour. Its active growth period is spring, summer, fall. USDA rates its lifespan as long.
What the site needs to provide
USDA records it across sites receiving 32 to 55 inches of annual precipitation. It needs at least 110 frost-free days to finish its season. It roots to at least 12 inches. Fertility requirement: high.
Propagating it
Propagate it from cuttings, container stock and sprigs. Its seed spreads at a slow rate. It spreads vegetatively at a rapid rate.
Resilience and wildlife
Its fire tolerance is rated low. Its growth form is recorded as rhizomatous.
Role in a guild
Herb layer. In a layered planting this is the herbaceous middle — perennials and grasses that fill the space between ground cover and shrubs. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Osmunda
- cinnamon fern Osmunda cinnamomea
- royal fern Osmunda regalis
Similar role and hardiness
- sweetflag Acorus americanus
- calamus Acorus calamus
- common yarrow Achillea millefolium
- western yarrow Achillea millefolium
- redtop Agrostis gigantea
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol OSCL2, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
- Quoted from USDA PLANTS: active growth period, Bloom, Bloom end, cold stratification, Drought tolerance, fall conspicuous, fertility requirement, fire tolerance, Flower color, flower conspicuous, foliage color, foliage porosity winter, foliage texture, frost free days min, fruit conspicuous, growth form, Growth rate, Hardiness zones, Lifecycle, lifespan, Light, Mature height, Minimum temperature, Native status, Nitrogen fixation, Nursery availability, precipitation max in, precipitation min in, propagation, resprout ability, root depth in, seed spread rate, Soil pH, Soil pH (upper), Tolerance of wet soil, Toxicity, Type, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer.
Read our full data sources and methodology.
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