North America Native Plant

Intermediate Mermaidweed

Botanical name: Proserpinaca intermedia

USDA symbol: PRIN2

Life cycle: perennial

Habit: forb

Native status: Native to Canada âš˜ Native to the lower 48 states  

Intermediate Mermaidweed: A Hidden Gem for Your Wetland Garden If you’re looking to create an authentic wetland garden or restore a natural bog area, you might want to get acquainted with intermediate mermaidweed (Proserpinaca intermedia). This unassuming native aquatic plant might not win any beauty contests, but it plays an ...

Rare plant alert!

Region: New Jersey

Status: Highlands Listed, S3: New Jersey Highlands region ⚘ 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 ⚘

Intermediate Mermaidweed: A Hidden Gem for Your Wetland Garden

If you’re looking to create an authentic wetland garden or restore a natural bog area, you might want to get acquainted with intermediate mermaidweed (Proserpinaca intermedia). This unassuming native aquatic plant might not win any beauty contests, but it plays an important role in wetland ecosystems and can be a valuable addition to specialized water gardens.

What Exactly Is Intermediate Mermaidweed?

Intermediate mermaidweed is a perennial forb – basically a soft-stemmed plant without woody growth above ground. Don’t expect showy flowers or dramatic foliage; this plant is all about function over form. It’s perfectly adapted to life in wet conditions, spending most of its time with its roots underwater or in saturated soil.

Where Does It Call Home?

This native North American species has quite an impressive range, naturally occurring from southeastern Canada down through the eastern United States. You’ll find it growing wild in states including Alabama, Connecticut, Florida, Georgia, Louisiana, Massachusetts, Michigan, Mississippi, New Jersey, North Carolina, Pennsylvania, Rhode Island, South Carolina, Tennessee, and Virginia, plus Nova Scotia in Canada.

Why Consider This Plant for Your Garden?

Here’s where things get interesting – intermediate mermaidweed is what botanists call an obligate wetland plant. This means it almost always occurs in wetlands and is perfectly suited for those challenging wet spots in your landscape where other plants struggle.

If you’re dealing with:

  • Persistently soggy areas in your yard
  • Rain garden projects
  • Pond edge plantings
  • Bog garden creation
  • Native wetland restoration efforts

Then intermediate mermaidweed could be your new best friend.

Important Conservation Note

Before you rush out to find this plant, there’s something crucial to know: in New Jersey, intermediate mermaidweed has a rarity status of Highlands Listed, S3, meaning it’s uncommon and potentially vulnerable. If you’re interested in growing this species, please only source it from reputable native plant nurseries that propagate their own stock rather than collecting from wild populations.

Growing Intermediate Mermaidweed Successfully

The good news is that if you can provide the right conditions, this plant is relatively low-maintenance. Here’s what you need to know:

Perfect Growing Conditions

  • Water requirements: Consistently moist to wet soil, or shallow standing water (up to 6 inches deep)
  • Light needs: Full sun to partial shade
  • Soil type: Any soil type as long as it stays saturated
  • Climate: Hardy in USDA zones 4-9

Planting and Care Tips

Once you’ve sourced your plants responsibly, establishing intermediate mermaidweed is straightforward. Plant it directly in saturated soil or submerge it in shallow water. The plant will adapt its form based on water levels – developing finely divided underwater leaves when submerged and different aerial leaves when growing above water.

Maintenance is minimal once established. The plant will naturally spread in suitable conditions, so you might need to manage its growth in smaller water features.

Setting Realistic Expectations

Let’s be honest – intermediate mermaidweed isn’t going to be the star of your garden show. Its flowers are small and wind-pollinated, so don’t expect to attract butterflies or hummingbirds. However, it does provide valuable ecosystem services like water filtration and habitat for aquatic insects and small wildlife.

Is This Plant Right for You?

Intermediate mermaidweed is perfect for gardeners who:

  • Are creating specialized wetland or bog gardens
  • Want to support native biodiversity
  • Need plants for consistently wet areas
  • Are involved in habitat restoration projects
  • Appreciate subtle, functional plants over flashy ornamentals

However, it’s probably not the best choice if you’re looking for showy flowers, drought-tolerant plants, or something for a typical perennial border.

While intermediate mermaidweed might not be the most glamorous addition to your plant collection, it serves an important ecological role and can be invaluable in the right setting. Just remember to source it responsibly and give it the wet feet it craves!

Intermediate Mermaidweed

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

Haloragales

Family

Haloragaceae R. Br. - Water Milfoil family

Genus

Proserpinaca L. - mermaidweed

Species

Proserpinaca intermedia Mack. - intermediate mermaidweed

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