North America Native Plant

Giant Cutgrass

Botanical name: Zizaniopsis miliacea

USDA symbol: ZIMI

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Synonyms: Zizania miliacea Michx. (ZIMI3)   

Giant Cutgrass: The Towering Native Wetland Wonder If you’re looking for a plant that makes a bold statement in wet areas, giant cutgrass (Zizaniopsis miliacea) might just be your answer. This impressive native perennial grass lives up to its name, reaching heights of up to 9 feet and creating dense, ...

Giant Cutgrass: The Towering Native Wetland Wonder

If you’re looking for a plant that makes a bold statement in wet areas, giant cutgrass (Zizaniopsis miliacea) might just be your answer. This impressive native perennial grass lives up to its name, reaching heights of up to 9 feet and creating dense, impenetrable stands that look like something from a nature documentary.

What Exactly Is Giant Cutgrass?

Giant cutgrass is a robust perennial grass native to the southeastern and south-central United States. Also known by its scientific name Zizaniopsis miliacea (formerly Zizania miliacea), this rhizomatous grass is a member of the same family as rice and wild rice. Don’t let the name fool you though – while it’s called cutgrass, it’s the plant that might do the cutting with its coarse, sharp-edged leaves!

Where Does It Call Home?

This wetland giant is native to 16 states across the lower 48, thriving from the Atlantic coast to Texas. You’ll find it naturally growing in Alabama, Arkansas, Florida, Georgia, Illinois, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia.

The Good, The Bad, and The Towering

Why you might want it:

  • Perfect for wetland restoration projects
  • Excellent erosion control along water bodies
  • Provides dense wildlife habitat and cover
  • Rapid growth rate fills in areas quickly
  • Extremely hardy in wet conditions
  • Native plant that supports local ecosystems

Why you might think twice:

  • Can grow up to 9 feet tall – it’s not subtle!
  • Spreads aggressively through rhizomes
  • Coarse texture isn’t everyone’s cup of tea
  • Limited ornamental appeal for formal gardens
  • Requires consistently wet conditions

Growing Giant Cutgrass Successfully

Giant cutgrass is what botanists call an obligate wetland plant, which is a fancy way of saying it absolutely, positively needs wet feet. This isn’t a plant for your average flower bed – it demands saturated soils and plenty of moisture.

Ideal Growing Conditions:

  • Moisture: High water requirements; thrives in saturated soils
  • Sunlight: Full sun (shade intolerant)
  • Soil: Adapts to coarse, medium, and fine-textured soils
  • pH Range: Very adaptable (4.3 to 9.0)
  • Hardiness: USDA zones 7-10
  • Precipitation: Needs 35-70 inches annually

Perfect Places for Giant Cutgrass

This isn’t your typical backyard border plant. Giant cutgrass shines in specific situations:

  • Pond and lake margins
  • Wetland restoration areas
  • Rain gardens (large ones!)
  • Bioswales and constructed wetlands
  • Naturalized areas near water features
  • Erosion control projects

Planting and Care Tips

The good news? Once established, giant cutgrass is remarkably low-maintenance. Here’s how to get started:

Planting:

  • Best planted in spring when active growth begins
  • Can be grown from seed (210,000 seeds per pound!) or container plants
  • Space plants considering their spreading nature
  • Ensure consistent moisture from day one

Ongoing Care:

  • Maintain consistent moisture – never let it dry out
  • Minimal fertilization needed (medium fertility requirements)
  • Cut back in late winter if desired
  • Monitor spread and contain if necessary

Wildlife and Ecosystem Benefits

While giant cutgrass might not be a pollinator magnet like wildflowers, it plays a crucial role in wetland ecosystems. The dense stands provide excellent cover for waterfowl, small mammals, and various bird species. The seeds, produced abundantly in fall and winter, serve as food for wildlife, and the extensive root system helps prevent soil erosion.

The Bottom Line

Giant cutgrass isn’t for everyone, and that’s perfectly okay. If you have a wet area that needs taming, want to support native wildlife, or are working on a wetland restoration project, this towering native could be exactly what you need. Just remember – this plant means business when it comes to size and spread, so plant with intention and plenty of space.

For smaller gardens or those without consistently wet areas, you might want to consider other native grasses that are more manageable. But if you’ve got the space and the water, giant cutgrass will reward you with rapid growth, excellent wildlife habitat, and the satisfaction of growing a true native that’s been thriving in American wetlands for centuries.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Atlantic and Gulf Coastal Plain

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Eastern Mountains and Piedmont

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Great Plains

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Midwest

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Giant Cutgrass

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

Poaceae Barnhart - Grass family

Genus

Zizaniopsis Döll & Asch. - cutgrass

Species

Zizaniopsis miliacea (Michx.) Döll & Asch. - giant cutgrass

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