North America Native Plant

Flatsedge

Botanical name: Cyperus ×deamii

USDA symbol: CYDE9

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Flatsedge: A Lesser-Known Native Sedge for Specialized Gardens Meet Cyperus ×deamii, commonly known as flatsedge – a unique native sedge that’s flying under the radar in most gardening circles. This perennial grass-like plant belongs to the sedge family (Cyperaceae), and while it might not be the showiest plant in your ...

Flatsedge: A Lesser-Known Native Sedge for Specialized Gardens

Meet Cyperus ×deamii, commonly known as flatsedge – a unique native sedge that’s flying under the radar in most gardening circles. This perennial grass-like plant belongs to the sedge family (Cyperaceae), and while it might not be the showiest plant in your garden, it represents an interesting piece of American botanical heritage that deserves a closer look.

Where Does Flatsedge Call Home?

This native flatsedge has a rather exclusive address list in the United States. You’ll find Cyperus ×deamii naturally occurring in just three states: Delaware, Indiana, and New Jersey. It’s quite the select club! This limited distribution makes it a special addition for gardeners in these regions who are passionate about growing truly local natives.

What Makes This Sedge Special?

As a hybrid species (indicated by the × in its scientific name), flatsedge represents a fascinating example of natural plant breeding. Like other sedges, it’s a grass-like perennial that brings a different texture and ecological function to your garden compared to true grasses. Sedges are often distinguished by their triangular stems – remember the old botanical saying: sedges have edges!

Should You Grow Flatsedge in Your Garden?

Here’s where things get interesting (and a bit challenging). Because Cyperus ×deamii is a hybrid with limited distribution, detailed growing information is scarce compared to more common native plants. However, if you’re located within its native range and are passionate about growing truly local species, this flatsedge could be a worthwhile addition to your native plant collection.

Growing Conditions and Care

While specific growing requirements for this particular hybrid aren’t well-documented, we can make some educated assumptions based on its sedge family characteristics:

  • Likely prefers moist to wet soil conditions (typical of most sedges)
  • Probably tolerates a range of light conditions from partial shade to full sun
  • May be suitable for rain gardens, pond edges, or naturally wet areas
  • Being a perennial, it should return year after year once established

The Challenge of Growing Flatsedge

Let’s be honest – finding this particular flatsedge at your local nursery is going to be like searching for a needle in a haystack. Its limited distribution and hybrid status mean it’s not commercially available through typical gardening channels. If you’re determined to grow it, you might need to:

  • Connect with native plant societies in Delaware, Indiana, or New Jersey
  • Look for specialized native plant nurseries in its range
  • Participate in seed swaps with other native plant enthusiasts

Alternatives to Consider

If you’re drawn to the idea of native sedges but can’t source Cyperus ×deamii, consider these more readily available alternatives:

  • Fox sedge (Carex vulpinoidea)
  • Pennsylvania sedge (Carex pensylvanica)
  • Wool grass (Scirpus cyperinus)
  • Other native Cyperus species in your region

The Bottom Line

Cyperus ×deamii represents one of those fascinating botanical treasures that’s more interesting for what it represents than for its garden practicality. If you’re a native plant purist living within its limited range and you can source it responsibly, it could be a unique addition to a specialized wet garden or naturalized area. However, for most gardeners, focusing on more readily available native sedges will give you similar ecological benefits with far less hunting involved.

Sometimes the most rewarding plants are the ones that make us work a little harder – but make sure the effort matches your gardening goals and available time!

Flatsedge

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Cyperaceae Juss. - Sedge family

Genus

Cyperus L. - flatsedge

Species

Cyperus ×deamii O'Neill (pro sp.) [esculentus × strigosus] - flatsedge

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA