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May grass

Phalaris caroliniana

Last reviewed: November 2026

May grass (Phalaris caroliniana) is a annual grass native to AL, AR, AZ, CA and 20 more states. It blooms in April, May, and June. The flowers draw wind-pollinated.

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May grass (Phalaris caroliniana)
Photo: (c) Sam Kieschnick, some rights reserved (CC BY), uploaded by Sam Kieschnick

Toxicity unknown

May grass (Phalaris caroliniana) 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.

Light

full sun

Water

high

Size

24"–48" H × 12"–18" W

Bloom

Apr, May, Jun

Native to

AL, AR, AZ, CA and 20 more states

Pollinators

wind-pollinated

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 461 programs across 44 states, each with a link to the provider and the date we last checked it.

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Browse plants for this ecoregion

Central California Foothills and Coastal MountainsCentral California ValleyArizona/New Mexico MountainsChihuahuan DesertsHigh PlainsSouthwestern TablelandsCentral Great PlainsCross TimbersEdwards PlateauSouthern Texas PlainsTexas Blackland PrairiesEast Central Texas PlainsWestern Gulf Coastal PlainSouth Central PlainsOzark HighlandsCentral Irregular PlainsPiedmontMiddle Atlantic Coastal PlainSoutheastern PlainsMississippi Alluvial PlainMississippi Valley Loess PlainsSouthern Coastal PlainMadrean ArchipelagoSonoran Basin and RangeSouthern California/Northern Baja Coast

An upright annual grass with narrow leaves and dense, compact cylindrical seed heads that ripen in late spring. It grows in wet, seasonally flooded prairie and low ground.

Growing May grass

Grow May grass in full sun and high water. Mature plants reach 24 to 48 inches tall and spread 12 to 18 inches wide.

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Wildlife value

The abundant seed is an important food source for wintering and migrating songbirds and waterfowl.

Common questions

How much sun does May grass need?
May grass grows best in full sun conditions.
When does May grass bloom?
May grass blooms in April, May, and June.
Where is May grass native?
May grass (Phalaris caroliniana) is native to AL, AR, AZ, CA and 20 more states, per the World Checklist of Vascular Plants (Kew).
What pollinators does May grass attract?
May grass draws wind-pollinated.

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.

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Ready to grow May grass? Add it to your garden in the Pollinator Patch App to track it and get season-by-season care guidance.

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