North America Native Plant

Washington Monkeyflower

Botanical name: Mimulus washingtonensis

USDA symbol: MIWA2

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Mimulus ampliatus A.L. Grant (MIAM)  âš˜  Mimulus patulus Pennell (MIPA14)  âš˜  Mimulus peduncularis A. Gray (MIPE6)   

Washington Monkeyflower: A Rare Native Gem for Wetland Gardens If you’re passionate about native plants and have a consistently wet spot in your garden, the Washington monkeyflower (Mimulus washingtonensis) might just capture your heart. This charming little annual brings delicate beauty to wetland gardens while supporting local ecosystems. However, before ...

Rare plant alert!

Region: Conservation status by state

Status: S1: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Uncertain taxonomy: ⚘ 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 ⚘

Region: Conservation status by state

Washington Monkeyflower: A Rare Native Gem for Wetland Gardens

If you’re passionate about native plants and have a consistently wet spot in your garden, the Washington monkeyflower (Mimulus washingtonensis) might just capture your heart. This charming little annual brings delicate beauty to wetland gardens while supporting local ecosystems. However, before you rush to add it to your shopping list, there’s something crucial you need to know about this special plant.

A Rare Pacific Northwest Native

Washington monkeyflower is a true native of the American West, naturally occurring in Idaho, Oregon, Washington, and Wyoming. This herbaceous annual forb belongs to a group of plants that lack woody stems and complete their entire life cycle in a single growing season. You might also see it listed under its former scientific names, including Mimulus ampliatus or Mimulus patulus, but Mimulus washingtonensis is the currently accepted botanical name.

Important Conservation Alert

Here’s where things get serious: Washington monkeyflower has a Global Conservation Status of S1, meaning it’s critically imperiled. With typically five or fewer known occurrences and very few remaining individuals (fewer than 1,000), this plant is extremely rare and vulnerable to extinction. If you’re considering growing this species, please only source it from reputable native plant nurseries that propagate from legally collected, responsibly sourced material. Never collect seeds or plants from wild populations.

What Makes It Special

This delicate annual produces small, tubular yellow flowers that are characteristic of the monkeyflower family. The blooms attract bees and other small pollinators, making it a valuable addition to native plant gardens focused on supporting local wildlife. As an annual, it completes its entire life cycle in one growing season, potentially self-seeding under ideal conditions.

Perfect for Wetland Gardens

Washington monkeyflower has earned Obligate Wetland status across all regions where it grows, meaning it almost always occurs in wetland environments. This makes it an excellent choice for:

  • Rain gardens and bioswales
  • Bog gardens and naturalized wet areas
  • Wetland restoration projects
  • Edges of ponds or water features
  • Consistently moist native plant gardens

Growing Conditions and Care

Success with Washington monkeyflower depends entirely on providing the right moisture conditions. This plant demands:

  • Soil moisture: Consistently wet to moist soil – never allow it to dry out
  • Light: Full sun to partial shade
  • Soil type: Adaptable to various soil types as long as moisture is consistent
  • Hardiness: Suitable for USDA zones 4-8 (estimated based on native range)

Since it’s an annual, you’ll need to rely on self-seeding or replant each year. In ideal conditions with consistent moisture, it may naturalize and return on its own.

Should You Grow Washington Monkeyflower?

This native beauty can be a wonderful addition to the right garden, but it’s not for everyone. Consider Washington monkeyflower if you:

  • Have a naturally wet area or maintained wetland garden
  • Are committed to supporting native plant conservation
  • Can source plants or seeds responsibly
  • Want to support native pollinators
  • Enjoy the challenge of growing rare plants

However, skip this plant if you have typical garden conditions with average moisture levels – it simply won’t survive without constant wetness.

The Bottom Line

Washington monkeyflower represents both an opportunity and a responsibility. By growing this critically imperiled native species in appropriate wetland gardens, you’re participating in conservation while creating habitat for native pollinators. Just remember: with great rarity comes great responsibility. Only grow this species if you can provide proper wetland conditions and source it responsibly from conservation-minded nurseries.

Your wetland garden could become a haven for this rare Pacific Northwest gem – and that’s something truly special.

Washington Monkeyflower

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Scrophulariales

Family

Scrophulariaceae Juss. - Figwort family

Genus

Mimulus L. - monkeyflower

Species

Mimulus washingtonensis Gandog. - Washington monkeyflower

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