North America Native Plant

Selfing Willowherb

Botanical name: Epilobium cleistogamum

USDA symbol: EPCL3

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Boisduvalia cleistogama Curran (BOCL)   

Selfing Willowherb: A Hidden Gem for California Wetland Gardens Meet the selfing willowherb (Epilobium cleistogamum), a charming little annual that’s perfectly designed for life in California’s wetland environments. While it might not win any beauty contests with its tiny flowers, this unassuming native plant plays an important role in supporting ...

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 ⚘

Selfing Willowherb: A Hidden Gem for California Wetland Gardens

Meet the selfing willowherb (Epilobium cleistogamum), a charming little annual that’s perfectly designed for life in California’s wetland environments. While it might not win any beauty contests with its tiny flowers, this unassuming native plant plays an important role in supporting local ecosystems and could be just what your wetland garden needs.

What Makes Selfing Willowherb Special?

This delicate annual forb belongs to the evening primrose family and has adapted beautifully to California’s unique wetland habitats. As its common name suggests, this plant has developed the fascinating ability to self-pollinate, ensuring reproduction even when pollinators are scarce. It’s also known by its former scientific name, Boisduvalia cleistogama, which you might encounter in older gardening references.

Where You’ll Find This California Native

Selfing willowherb is endemic to California, making it a true Golden State original. This specialized plant has evolved to thrive in the state’s wetland areas, from coastal regions to inland valleys. As an obligate wetland species, it’s almost exclusively found in consistently moist or wet environments.

A Plant with Specific Needs

Here’s where things get interesting – and a bit challenging. Selfing willowherb isn’t your typical garden center find, and for good reason. This annual has very particular growing requirements that make it suitable for specialized garden applications:

  • Moisture requirements: As an obligate wetland plant, it needs consistently wet or waterlogged soil
  • USDA Zones: Best suited for zones 8-10, matching California’s climate
  • Light needs: Performs well in full sun to partial shade
  • Soil type: Thrives in wet, often poorly-drained soils that would challenge most garden plants

Is Selfing Willowherb Right for Your Garden?

This unique native is perfect for gardeners who are:

  • Creating authentic wetland or bog gardens
  • Working on native plant restoration projects
  • Designing rain gardens or bioswales
  • Supporting local California ecosystems

However, it’s not ideal for traditional flower beds or drought-tolerant landscapes. Its beauty lies in its ecological function rather than showy blooms.

Ecological Benefits

While selfing willowherb may seem modest, it serves important ecological functions. Its small flowers provide nectar for tiny pollinators and beneficial insects that larger, showier plants might not attract. As part of wetland plant communities, it helps stabilize soil, filter water, and create habitat for various wetland creatures.

A Note About Availability

Selfing willowherb has a conservation status that suggests it may be uncommon in parts of its range. If you’re interested in growing this species, make sure to source seeds or plants from reputable native plant nurseries that practice ethical collection methods. Never collect from wild populations.

Growing Tips for Success

If you have the right conditions and can source this plant responsibly, here’s how to give it the best chance:

  • Location: Choose a consistently wet area of your garden
  • Timing: As an annual, it completes its life cycle in one growing season
  • Maintenance: Once established in suitable conditions, it’s relatively low-maintenance
  • Companions: Pair with other California wetland natives for an authentic ecosystem

The Bottom Line

Selfing willowherb isn’t for every gardener or every garden, but for those creating authentic California wetland habitats or restoration projects, it’s a valuable addition. This specialized native offers a chance to support local ecosystems while learning about the fascinating adaptations of California’s unique flora. Just remember – wet feet are absolutely essential for this little wetland warrior!

Selfing Willowherb

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Myrtales

Family

Onagraceae Juss. - Evening Primrose family

Genus

Epilobium L. - willowherb

Species

Epilobium cleistogamum (Curran) Hoch & P.H. Raven - selfing willowherb

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