What growing conditions does Sium suave prefer?

Water parsley grows best in consistently wet to saturated soils, often standing in shallow water along ditches, marsh edges and slow streams, with part sun to full sun exposure.

When does Sium suave bloom?

It blooms in June, July and August, sending up flat topped umbels of small white flowers typical of the carrot family.

What insects visit Sium suave flowers?

Bees, beetles and flies commonly visit the flowers for pollen and nectar, making it a useful nectar source in wetland plant communities during summer.

How much water does Sium suave need to thrive?

This forb needs a consistently high moisture site and does not tolerate dry soil well, so it is best suited to wet meadows, pond margins and ditch banks.

Is Water-parsley HOA-friendly?

Water-parsley takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Water-parsley

Name: Pollinator Patch
Author: Pollinator Patch

Sium suave

Last reviewed: September 2026

Sium suave, known as water parsley, grows in marshes, wet meadows and streambanks across much of the United States and produces flat clusters of small white flowers from June through August.

Toxicity unknown

Water-parsley (Sium suave) 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

part sun

Water

high

Size

12"–48" H × 8"–24" W

Bloom

Jun, Jul, Aug

Native to

AL, AR, AZ, CA and 43 more states

Pollinators

bees, beetles, flies

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 area

Browse plants for this ecoregion

Coast Range Puget Lowland Marine West Coast Forest Northwestern Forested Mountains Sierra Nevada Central California Foothills and Coastal Mountains Central California Valley North American Deserts Central Basin and Range Southern Rockies Central Great Plains Ozark Highlands Central Irregular Plains Northwestern Glaciated Plains Great Plains Piedmont 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 Erie Drift Plain Middle Atlantic Coastal Plain Northern Piedmont Southeastern Plains Ridge and Valley Central Appalachians Western Allegheny Plateau Interior River Valleys and Hills Mississippi Alluvial Plain Southern Coastal Plain Acadian Plains and Hills Eastern Great Lakes Lowlands Atlantic Coastal Pine Barrens

Water-parsley is a native wetland perennial that thrives in consistently moist to wet soils and partial sun conditions. It produces small white flower clusters during summer months and grows 1-4 feet tall with a somewhat spreading habit. This plant requires constant moisture and is best suited for rain gardens, pond edges, or areas with poor drainage.

Growing Water-parsley

Grow Water-parsley in part sun and high water. Mature plants reach 12 to 48 inches tall and spread 8 to 24 inches wide. Expect moderate maintenance to keep it looking intentional in a front yard.

In an HOA neighborhood

Water-parsley takes more care to keep looking intentional in a front yard. Maintenance level: moderate. Consider it for backyard or mid-zone beds rather than the street edge.

Works well in: backyard only.

Looks wild and informal in appearance
Requires consistently wet conditions that may appear unkempt
Can become quite tall and sprawling

Wildlife value

The summer blooms attract various pollinators including native bees, beetles, and flies. As a native wetland species, it provides important habitat and food sources for moisture-loving insects.

Common questions

What growing conditions does Sium suave prefer?: Water parsley grows best in consistently wet to saturated soils, often standing in shallow water along ditches, marsh edges and slow streams, with part sun to full sun exposure.
When does Sium suave bloom?: It blooms in June, July and August, sending up flat topped umbels of small white flowers typical of the carrot family.
What insects visit Sium suave flowers?: Bees, beetles and flies commonly visit the flowers for pollen and nectar, making it a useful nectar source in wetland plant communities during summer.
How much water does Sium suave need to thrive?: This forb needs a consistently high moisture site and does not tolerate dry soil well, so it is best suited to wet meadows, pond margins and ditch banks.
Is Water-parsley HOA-friendly?: Water-parsley 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 vouchered herbarium specimen records and regional native plant society lists. 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 Water-parsley? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

Add this plant to your garden

iPhone app Android app

Planning a bed around it? Start a free plan with this plant

Not sure where to start? Take the 2-minute yard quiz