Tapertip Flatsedge Cyperus acuminatus
Tapertip Flatsedge is an annual grass native to Canada and the lower 48 states. It grows to 1.3 ft and blooms May in full sun – part shade, with green fruit.
More about this plant
Cyperus acuminatus is a common species of sedge known by several common names, including tapertip flatsedge and pale umbrella-sedge. This plant is native to North America, where it is widespread across the Great Plains and the western United States, with scattered populations in the eastern US as well as in Saskatchewan, Tamaulipas and Coahuila. Wikipedia →
Growing & care
USDA PLANTS · TRY- Sun
- Full sun – part shade
- Soil & moisture
- High moisture
- Soil pH
- 4.9–6.8
- Fertility need
- Medium
- Adapts to
- Medium (loam), Fine (clay)
- Hardiness
- USDA zone 4+
- Height
- 1.3 ft
- Spacing
- 2–3 ft apart from USDA planting density
- Spread
- None — clumping
- Growth rate
- Rapid
- Growth form
- Bunch
- Lifespan
- Annual · short-lived
- Foliage
- Broadleaf · fine texture
- Active growth
- Spring & summer
- Fruit
- Green persists into winter
- Flower colour
- Brown AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
- Propagate by
- Sprigs
- Seed starting
- No stratification needed
- Seeds ripen
- Summer – Autumn seed-collection / harvest window
- In the trade
- No known commercial source
- Resprouts if cut
- No
Sow timing keys off your local last- and first-frost dates.
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~5 caterpillar species
Cyperus supports ~5 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a modest genus.
Recorded feeding on Cyperus in North America, including:
+ 4 more species → ↑ show fewer
Related plants
More Cyperus →
How we know this (3) Methods & honest limits
We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.
Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (30) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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