North America Native Plant

Mosquito Waterwort

Botanical name: Elatine heterandra

USDA symbol: ELHE2

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Mosquito Waterwort: A Tiny Native Gem for Wetland Gardens If you’re looking to add authentic California native flair to your water garden or rain garden, you might want to consider mosquito waterwort (Elatine heterandra). This diminutive annual herb won’t win any beauty contests, but it plays an important ecological role ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Mosquito Waterwort: A Tiny Native Gem for Wetland Gardens

If you’re looking to add authentic California native flair to your water garden or rain garden, you might want to consider mosquito waterwort (Elatine heterandra). This diminutive annual herb won’t win any beauty contests, but it plays an important ecological role in California’s seasonal wetlands and can be a fascinating addition for gardeners interested in creating naturalistic water features.

What Is Mosquito Waterwort?

Mosquito waterwort is a small annual forb native to California. As a forb, it’s a non-woody vascular plant that completes its entire life cycle in a single growing season. Don’t expect towering heights – this little guy stays close to the ground, forming small mats along pond edges, seasonal pools, and mudflats.

The plant produces tiny white to pinkish flowers that are easy to miss unless you’re looking closely. Its small, opposite leaves create a delicate texture that adds subtle interest to wetland plantings, though you’ll need to appreciate understated beauty to truly love this species.

Where Does It Grow?

This California native is found throughout the Golden State, where it naturally occurs in seasonal pools, pond margins, and other wetland areas. As an obligate wetland species, mosquito waterwort almost always occurs in wet conditions – it’s not adaptable to typical garden beds.

Should You Plant Mosquito Waterwort?

Here’s the thing about mosquito waterwort – it’s a specialist plant for specialist gardeners. You should consider growing it if you:

  • Have a water garden, rain garden, or seasonal wetland area
  • Want to support native California ecosystems
  • Appreciate subtle, naturalistic plantings over showy displays
  • Are creating habitat for small wetland wildlife

However, there’s an important caveat: mosquito waterwort has a conservation status of S3S4, meaning its populations may be somewhat limited. If you decide to grow this species, make sure you source seeds or plants responsibly from reputable native plant nurseries – never collect from wild populations.

Growing Conditions and Care

Successfully growing mosquito waterwort is all about understanding its wetland requirements:

Water Requirements: This plant needs consistent moisture or seasonal flooding. It won’t survive in typical garden conditions – think pond edges, rain garden low spots, or areas that stay wet for extended periods.

Light: Full sun to partial shade works well, though it seems to prefer brighter conditions in its natural habitat.

Hardiness: Being a California native, it’s likely hardy in USDA zones 8-10, matching California’s Mediterranean climate.

Soil: Tolerates various soil types as long as they stay wet – from clay to sandy soils in wetland conditions.

Planting and Propagation

Since mosquito waterwort is an annual, you’ll need to establish it from seed each year or allow it to self-seed in suitable conditions. Plant seeds in fall or winter in areas that will receive seasonal flooding or consistent moisture. The seeds need wet conditions to germinate and establish successfully.

Once established, this low-maintenance native requires little care beyond ensuring adequate moisture. In the right conditions, it may self-seed and return year after year, creating naturalized colonies.

Ecological Benefits

While mosquito waterwort may not be a major pollinator magnet, its tiny flowers can attract small insects, and its seeds likely provide food for wetland birds and small wildlife. As part of California’s native wetland plant community, it contributes to the complex web of relationships that support local ecosystems.

The Bottom Line

Mosquito waterwort isn’t for every garden or every gardener. It requires specific wet conditions, offers subtle rather than showy appeal, and needs responsible sourcing due to its conservation status. But for the right water garden enthusiast who wants to support California’s native wetland ecosystems, this little annual can be a rewarding addition to a naturalistic planting scheme.

If you’re not quite ready for such a specialized plant, consider other California native wetland species that might be easier to source and establish while still supporting local ecosystems.

Mosquito Waterwort

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Theales

Family

Elatinaceae Dumort. - Waterwort family

Genus

Elatine L. - waterwort

Species

Elatine heterandra H. Mason - mosquito waterwort

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA