How much sun does Northern Water-starwort need?

Northern Water-starwort grows best in part sun conditions.

When does Northern Water-starwort bloom?

Northern Water-starwort blooms in May, June, July, and August.

Where is Northern Water-starwort native?

Northern Water-starwort (Callitriche hermaphroditica) is native to CO, ID, IL, MN and 10 more states, per the World Checklist of Vascular Plants (Kew).

Is Northern Water-starwort toxic to livestock?

The USDA PLANTS Database does not flag Northern Water-starwort as toxic to livestock.

Is Northern Water-starwort HOA-friendly?

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

Northern Water-starwort

Name: Pollinator Patch
Author: Pollinator Patch

Callitriche hermaphroditica

Last reviewed: August 2026

Toxicity unknown

Northern Water-starwort (Callitriche hermaphroditica) 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 Northern Water-starwort as toxic to livestock.

Light

part sun

Water

high

Size

2"–12" H × 2"–12" W

Bloom

May, Jun, Jul, Aug

Native to

CO, ID, IL, MN and 10 more states

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.

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Browse plants for this ecoregion

Coast Range Northwestern Forested Mountains North American Deserts Southern Rockies Northwestern Glaciated Plains Northwestern Great Plains Northern Glaciated Plains Great Plains Northern Lakes and Forests

Northern water-starwort is a small aquatic annual that forms low mats of tiny star-shaped leaves in shallow water or very wet soil. This native plant produces inconspicuous flowers from late spring through summer and requires consistently saturated conditions to thrive.

In an HOA neighborhood

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

Works well in: backyard only.

Requires standing water or bog conditions
Very informal wetland appearance
Dies back completely as annual

Wildlife value

This aquatic plant provides habitat for small invertebrates and amphibians in water features. While not a major pollinator plant, it supports wetland ecosystem health.

Common questions

How much sun does Northern Water-starwort need?: Northern Water-starwort grows best in part sun conditions.
When does Northern Water-starwort bloom?: Northern Water-starwort blooms in May, June, July, and August.
Where is Northern Water-starwort native?: Northern Water-starwort (Callitriche hermaphroditica) is native to CO, ID, IL, MN and 10 more states, per the World Checklist of Vascular Plants (Kew).
Is Northern Water-starwort toxic to livestock?: The USDA PLANTS Database does not flag Northern Water-starwort as toxic to livestock.
Is Northern Water-starwort HOA-friendly?: Northern Water-starwort takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

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

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