redroot flatsedge
Cyperus erythrorhizos · Cyperaceae
redroot flatsedge (Cyperus erythrorhizos) is a perennial grass or grass-like plant in the Cyperaceae family. It is native to North America. USDA records it as hardy in zone 10 and warmer, down to about 37°F.
At a glance
| Type | graminoid USDA |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 2.5 ft USDA |
| Light | full-sun USDA |
| Water need | medium USDA |
| Growth rate | rapid USDA |
| Soil pH | 5–6.5 USDA |
| Bloom | July USDA |
| Flower color | Green USDA |
| Hardiness zones | 10 and warmer USDA |
| Guild layer | herb-layer Derived |
| Nursery availability | Contracting Only 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 needs full sun. USDA rates it as having moderate water needs. Its drought tolerance is rated medium. It handles periodically wet ground (USDA rates its anaerobic tolerance medium). It is recorded on soils from pH 5 to 6.5 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 10.
Size and growth
At maturity it reaches about 2.5 ft, making it about knee height. It grows quickly.
Bloom period
USDA records a bloom period of July. Flowers are green.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is dark green, coarse in texture. Its flowers are not conspicuous — a plant for form and foliage. Its active growth period is summer and fall. USDA rates its lifespan as short, so plan on replacing or resowing it rather than treating it as permanent structure.
What the site needs to provide
USDA records it across sites receiving 14 to 50 inches of annual precipitation. The low end of that band is genuinely arid, so it has a wide tolerance for dry country. It needs at least 90 frost-free days to finish its season. It roots to at least 10 inches. Fertility requirement: low — no feeding needed on ordinary garden soil.
Propagating it
Sprigs is the only propagation method USDA lists. Its seed spreads at a moderate rate. It does not spread vegetatively, so it will stay where you put it.
Resilience and wildlife
Its fire tolerance is rated low. Its growth form is recorded as bunch.
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 Cyperus
- tapertip flatsedge Cyperus acuminatus
- slender flatsedge Cyperus bipartitus
- poorland flatsedge Cyperus compressus
- yellow nutsedge Cyperus esculentus
Similar role and hardiness
- digitgrass Digitaria eriantha
- billion-dollar grass Echinochloa frumentacea
- blunt spikerush Eleocharis obtusa
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol CYER2, 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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