Big Cordgrass
Spartina cynosuroides
Last reviewed: August 2026
Big cordgrass is a tall wetland grass that grows in full sun along tidal and brackish marshes from the Northeast through the Gulf Coast, blooming from July through September.
Toxicity unknown
Big Cordgrass (Spartina cynosuroides) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
The USDA PLANTS Database (opens in new tab) does not flag Big Cordgrass as toxic to livestock.
Light
full sun
Water
high
Size
48"–96" H × 24"–48" W
Bloom
Jul, Aug, Sep
Native to
AL, CT, DE, FL and 13 more states
Pollinators
bees, beetles
Before you buy
Your city may pay you to plant this
Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.
Find rebates in your areaBrowse plants for this ecoregion
Big cordgrass is a tall, robust native grass that forms substantial clumps and thrives in wet conditions. It produces feathery seed heads in late summer and turns golden-brown in fall before going dormant in winter.
Growing Big Cordgrass
Grow Big Cordgrass in full sun and high water. Mature plants reach 48 to 96 inches tall and spread 24 to 48 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Big Cordgrass takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Extremely tall height (up to 8 feet) exceeds typical HOA limits
- Can appear wild and unkempt during growing season
- Large spread creates dominant presence that may seem uncontrolled
Wildlife value
This grass supports bees and beetles during its summer blooming period. The dense growth provides nesting habitat for birds and the seeds feed wildlife through fall and winter.
Common questions
- When does big cordgrass bloom?
- Big cordgrass produces its tall flowering spikes from July through September, standing well above the surrounding marsh grasses.
- What insects visit big cordgrass flowers?
- Bees and beetles are commonly seen visiting the flowers of big cordgrass for pollen during its summer bloom period.
- How much water does big cordgrass need?
- This grass thrives in consistently wet to flooded soils, such as tidal marshes and brackish wetland edges, and does not tolerate dry conditions well.
- What light does big cordgrass prefer?
- Big cordgrass grows best in full sun and can tolerate lightly filtered or partial sun but will thin out in heavier shade.
- Is Big Cordgrass toxic to livestock?
- The USDA PLANTS Database does not flag Big Cordgrass as toxic to livestock.
- Is Big Cordgrass HOA-friendly?
- Big Cordgrass takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.
Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
If something looks wrong
Common plant problems, and what to check first
These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.
- It is dying right after planting
- Leaves turning yellow
- Wilting even though I watered it
- Brown crispy leaf tips
- Bugs on the plant
Ready to grow Big Cordgrass? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Planning a bed around it? Start a free plan with this plant
Not sure where to start? Take the 2-minute yard quiz