What growing conditions does Acorus americanus need?

It does best in full sun with consistently high moisture, such as marsh edges, pond margins and shallow standing water.

When does Acorus americanus bloom?

It typically flowers in May and June, producing a short, fleshy greenish yellow spadix.

What insects pollinate Acorus americanus?

Flies and small beetles are the main visitors, attracted to the compact flower spike typical of the arum family.

Can Acorus americanus tolerate some shade?

It can handle part sun conditions along stream banks, but it flowers and spreads most vigorously in full sun.

American sweetflag

Name: Pollinator Patch
Author: Pollinator Patch

Acorus americanus

Last reviewed: November 2026

Acorus americanus is an emergent wetland forb that grows in full sun along marsh edges, pond margins and slow streams, blooming in May and June with a short greenish yellow flower spike.

Watering reminders and freeze alerts for American sweetflag, free in the app.

Toxicity unknown

American sweetflag (Acorus americanus) 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

18"–36" H × 12"–24" W

Bloom

May, Jun

Native to

CO, CT, DC, IA and 22 more states

Pollinators

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

Find rebates in your area

Picture natives in your own yard

Upload a photo of your yard and Patch Vision shows a rendering of it planted with natives for your region, like American sweetflag.

Try it with your yard

Browse plants for this ecoregion

Great Plains Northern Glaciated Plains Western Corn Belt Plains Northern Forests Northern Lakes and Forests North Central Hardwood Forests Driftless Area Southeastern Wisconsin Till Plains Central Corn Belt Plains Eastern Corn Belt Plains Southern Michigan/Northern Indiana Drift Plains Huron/Erie Lake Plains Northeastern Highlands Northeastern Coastal Zone Northern Allegheny Plateau Acadian Plains and Hills Eastern Great Lakes Lowlands

An emergent wetland plant with flat sword-like leaves that release a sweet spicy scent when bruised, and an inconspicuous green flower spike angled off the stem. It spreads by rhizome in shallow standing water and saturated soil.

Growing American sweetflag

Grow American sweetflag in full sun and high water. Mature plants reach 18 to 36 inches tall and spread 12 to 24 inches wide.

Wildlife value

Dense colonies stabilize shorelines and provide cover for wetland birds and amphibians.

Common questions

What growing conditions does Acorus americanus need?: It does best in full sun with consistently high moisture, such as marsh edges, pond margins and shallow standing water.
When does Acorus americanus bloom?: It typically flowers in May and June, producing a short, fleshy greenish yellow spadix.
What insects pollinate Acorus americanus?: Flies and small beetles are the main visitors, attracted to the compact flower spike typical of the arum family.
Can Acorus americanus tolerate some shade?: It can handle part sun conditions along stream banks, but it flowers and spreads most vigorously in full sun.

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.

See all plant problem guides

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

Add this plant to your garden

iPhone app Android app