North America Native Plant

Manyspike Flatsedge

Botanical name: Cyperus polystachyos var. polystachyos

USDA symbol: CYPOP2

Life cycle: annual

Habit: grass

Native status: Native to Hawaii âš˜ It's either native or not native in Pacific Basin excluding Hawaii âš˜ Native to Puerto Rico âš˜ Native to the U.S. Virgin Islands  

Synonyms: Cyperus paniculatus Rottb. (CYPA20)  âš˜  Cyperus polystachyos Rottb. var. leptostachyus Boeckeler (CYPOL3)  âš˜  Cyperus polystachyos Rottb. var. pallidus Hillebr. (CYPOP)  âš˜  Cyperus polystachyos Rottb. var. paniculatus (Rottb.) C.B. Clarke (CYPOP3)  âš˜  Mariscus polystachyos auct. non A. Rich. (MAPO8)  âš˜  Pycreus polystachyos (Rottb.) P. Beauv. (PYPO)   

Manyspike Flatsedge: A Humble Native Sedge for Tropical Gardens If you’re looking for a low-maintenance native plant that won’t steal the spotlight but will quietly do its job in your tropical or subtropical garden, meet the manyspike flatsedge. This unassuming little sedge might not win any beauty contests, but it’s ...

Manyspike Flatsedge: A Humble Native Sedge for Tropical Gardens

If you’re looking for a low-maintenance native plant that won’t steal the spotlight but will quietly do its job in your tropical or subtropical garden, meet the manyspike flatsedge. This unassuming little sedge might not win any beauty contests, but it’s got some serious practical benefits that make it worth considering for the right garden setting.

What Is Manyspike Flatsedge?

Manyspike flatsedge (Cyperus polystachyos var. polystachyos) is a grass-like plant that’s actually a member of the sedge family, not a true grass. You might also hear it called simply sedge. This native plant can behave as either an annual or perennial depending on growing conditions, giving it some flexibility in how it fits into your landscape.

Don’t let the humble appearance fool you – this little plant is a workhorse when it comes to handling wet conditions and preventing soil erosion.

Where Does It Call Home?

This sedge is a true tropical and subtropical native, naturally occurring in Hawaii, Puerto Rico, the U.S. Virgin Islands, Guam, Palau, and other Pacific islands. If you’re gardening in these areas, you’re working with a plant that’s perfectly adapted to your local conditions.

Why You Might Want to Plant It

Here’s where manyspike flatsedge really shines:

  • Native plant gardening: If you’re committed to using native species, this sedge is an authentic choice for tropical and subtropical regions
  • Problem solver: Got a wet, boggy area where other plants struggle? This sedge thrives in moist to wet soils
  • Low maintenance: Once established, it pretty much takes care of itself
  • Erosion control: The root system helps stabilize soil, making it useful on slopes or areas prone to washout
  • Naturalistic landscapes: Perfect for creating that wild look in native plant communities

Why You Might Skip It

Let’s be honest – this isn’t a showstopper plant:

  • Limited visual appeal: The brownish flower clusters and narrow foliage won’t provide dramatic color or texture
  • Can spread: It spreads by underground stems and may self-seed, which could be problematic in small, formal gardens
  • Climate limitations: Only suitable for USDA zones 9-11, so not an option for cooler climates

Growing Manyspike Flatsedge Successfully

The good news is that if you’re in the right climate zone, this plant is pretty forgiving:

Location and Soil

  • Choose a spot with full sun to partial shade
  • Ensure consistently moist to wet soil – this plant can even handle occasional flooding
  • Works well near water features, in rain gardens, or naturally wet areas of your property

Planting and Care

  • Plant in spring when temperatures are consistently warm
  • Space plants according to how much spread you want – they’ll fill in naturally
  • Water regularly until established, then natural rainfall should be sufficient in most tropical climates
  • Minimal fertilization needed – these plants are adapted to nutrient-poor wetland soils

Maintenance

  • Very low maintenance once established
  • May need occasional division if it spreads beyond desired areas
  • Remove old growth if desired, but not necessary for plant health

The Bottom Line

Manyspike flatsedge isn’t going to be the star of your garden, but it’s an excellent supporting player for native plant enthusiasts in tropical and subtropical regions. If you have wet areas where other plants struggle, need help with erosion control, or simply want to support local ecosystems with native species, this humble sedge deserves consideration.

Just remember – it’s a plant that knows what it likes (wet feet and warm weather) and where it belongs (naturalistic settings rather than formal flower beds). Give it the right conditions, and it’ll reward you with years of low-maintenance, authentic native beauty.

Manyspike 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 polystachyos Rottb. - manyspike flatsedge

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