North America Native Plant

Hillebrand’s Flatsedge

Botanical name: Cyperus hillebrandii var. hillebrandii

USDA symbol: CYHIH2

Life cycle: perennial

Habit: grass

Native status: Native to Hawaii  

Synonyms: Cyperus hillebrandii Boeckeler var. helleri Kük. (CYHIH)  âš˜  Cyperus hillebrandii Boeckeler var. mauiensis (Hillebr.) Kük. (CYHIM)  âš˜  Mariscus hillebrandii (Boeckeler) T. Koyama (MAHI3)   

Hillebrand’s Flatsedge: A Hidden Gem for Hawaiian Native Gardens If you’re passionate about native Hawaiian plants and looking for something a little different from the usual suspects, let me introduce you to Hillebrand’s flatsedge (Cyperus hillebrandii var. hillebrandii). This unassuming sedge might not have the flashy flowers of a hibiscus, ...

Rare plant alert!

Region: Conservation status by state

Status: S3T3: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘ Subspecies or variety is vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals. ⚘

Hillebrand’s Flatsedge: A Hidden Gem for Hawaiian Native Gardens

If you’re passionate about native Hawaiian plants and looking for something a little different from the usual suspects, let me introduce you to Hillebrand’s flatsedge (Cyperus hillebrandii var. hillebrandii). This unassuming sedge might not have the flashy flowers of a hibiscus, but it packs a serious punch when it comes to authenticity and ecological value in your garden.

What Makes This Plant Special?

Hillebrand’s flatsedge is a true Hawaiian native – not just naturalized, but actually endemic to the Hawaiian Islands. As a perennial sedge, it brings that distinctive grass-like texture that’s perfect for creating natural-looking landscapes. Don’t let the name fool you; while it’s called a flatsedge, it’s actually part of the sedge family (Cyperaceae), giving your garden that authentic wetland feel without the high maintenance.

Where You’ll Find It Growing Wild

This charming sedge calls Hawaii home and only Hawaii. It’s endemic to the islands, meaning you won’t find it growing naturally anywhere else in the world. This makes it extra special for Hawaiian gardeners who want to showcase truly local flora.

A Word of Caution: Rarity Matters

Here’s something important to know before you start planning where to plant it: Hillebrand’s flatsedge has a conservation status of S3T3, which indicates some level of conservation concern. This doesn’t mean you shouldn’t grow it – quite the opposite! Growing native plants helps preserve them. However, it does mean you should be extra careful about sourcing your plants responsibly. Always purchase from reputable native plant nurseries that propagate their stock rather than collecting from wild populations.

Why Your Garden (and Local Wildlife) Will Love It

While this sedge might seem humble, it’s actually a multitasker in the garden:

  • Provides authentic Hawaiian character to native plant gardens
  • Offers habitat structure for native insects and small wildlife
  • Works beautifully in naturalistic landscapes and rain gardens
  • Low maintenance once established
  • Helps with erosion control in appropriate settings

Growing Hillebrand’s Flatsedge Successfully

The good news is that this native sedge isn’t particularly fussy once you understand its preferences. Like many Hawaiian natives, it appreciates:

  • Climate zones: USDA zones 10-12 (tropical conditions)
  • Light: Full sun to partial shade
  • Soil: Moist to wet soils – think rain garden conditions
  • Water: Consistent moisture, tolerates wet feet

Perfect Garden Companions

Hillebrand’s flatsedge plays well with other Hawaiian natives, especially those that enjoy similar moisture conditions. Consider pairing it with other native sedges, rushes, or moisture-loving Hawaiian plants to create an authentic ecosystem in your garden.

The Bottom Line

If you live in Hawaii (or a similar tropical climate) and want to support native biodiversity while creating a unique garden space, Hillebrand’s flatsedge deserves a spot on your plant list. Just remember to source it responsibly and give it the moist conditions it craves. Your local ecosystem will thank you, and you’ll have the satisfaction of growing something truly special – a plant that exists nowhere else on Earth!

While it might not be the showiest plant in your garden, sometimes the quiet champions are the ones that make the biggest difference. In a world where native plants are increasingly under pressure, every garden that welcomes them becomes a small sanctuary. And really, isn’t that what gardening is all about?

Hillebrand’s 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 hillebrandii Boeckeler - Hillebrand's flatsedge

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