North America Native Plant

Liquillo Mountain Clearweed

Botanical name: Pilea multicaulis

USDA symbol: PIMU3

Life cycle: perennial

Habit: subshrub

Native status: Native to Puerto Rico  

Luquillo Mountain Clearweed: A Rare Puerto Rican Treasure Worth Protecting If you’re passionate about native plants and conservation, you’ve probably never heard of Luquillo Mountain clearweed (Pilea multicaulis). And honestly, that’s not surprising – this little-known Puerto Rican native is one of the island’s botanical treasures that’s flying completely under ...

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) ⚘

Luquillo Mountain Clearweed: A Rare Puerto Rican Treasure Worth Protecting

If you’re passionate about native plants and conservation, you’ve probably never heard of Luquillo Mountain clearweed (Pilea multicaulis). And honestly, that’s not surprising – this little-known Puerto Rican native is one of the island’s botanical treasures that’s flying completely under the radar. But should you add it to your garden? Well, that’s a complicated question that deserves a thoughtful answer.

What Makes This Plant Special?

Luquillo Mountain clearweed is a perennial herb that belongs to the nettle family, though don’t worry – it won’t sting you! This delicate forb grows as a small, soft-stemmed plant without any woody tissue, making it quite different from the shrubs and trees you might typically think of when imagining tropical plants.

What makes this plant truly remarkable isn’t its size or showiness – it’s its rarity and ecological importance. This little clearweed is found nowhere else on Earth except Puerto Rico, making it what botanists call an endemic species.

Where Does It Call Home?

Pilea multicaulis is native exclusively to Puerto Rico, where it grows in the wild only in very specific locations. This isn’t a plant you’ll find scattered across the island – it’s restricted to particular habitats that meet its very specific needs.

A Plant in Crisis: Understanding Its Rarity

Here’s where things get serious: Luquillo Mountain clearweed has a Global Conservation Status of S1, which means it’s critically imperiled. In plain English? There are likely fewer than 1,000 individual plants left in the wild, possibly as few as five known locations where it still grows. This puts it in the same category as some of the world’s most endangered species.

This extreme rarity means that if you’re considering growing this plant, you need to be incredibly responsible about it. We’re talking about a species that could disappear forever if we’re not careful.

Growing Conditions: Not for the Average Gardener

Even if you could responsibly source this plant (which is a big if), growing Luquillo Mountain clearweed is not for beginners. This species is classified as an obligate wetland plant in the Caribbean region, which means it almost always requires wetland conditions to survive.

Here’s what that means for your garden:

  • Water requirements: Consistently moist to saturated soil – think bog garden conditions
  • Climate needs: Tropical conditions similar to Puerto Rico (USDA zones 10-11)
  • Humidity: High humidity levels that mimic its native cloud forest environment
  • Light conditions: Likely prefers partial shade, typical of understory plants

Unless you live in a tropical climate and have experience maintaining wetland gardens, this plant would be extremely challenging to keep alive.

Should You Grow It?

Here’s my honest recommendation: unless you’re a botanical garden, research institution, or serious conservation organization with the proper expertise and permits, you probably shouldn’t attempt to grow Luquillo Mountain clearweed.

Why? Because:

  • Any specimens should come from carefully managed propagation programs, not wild collection
  • The plant requires very specialized growing conditions that are difficult to replicate
  • With so few plants left in the wild, every individual matters for conservation
  • There are many other Puerto Rican native plants that are more suitable for home gardens

How You Can Help Instead

If reading about this rare plant has sparked your interest in Puerto Rican native species, there are better ways to support conservation:

  • Support organizations working to protect Puerto Rico’s native plants
  • Learn about and grow other Puerto Rican natives that are more readily available
  • Advocate for habitat protection in Puerto Rico’s remaining natural areas
  • Spread awareness about the island’s unique and threatened plant species

The Bigger Picture

Luquillo Mountain clearweed represents something much larger than just one small plant – it’s a symbol of the incredible biodiversity that exists in Puerto Rico’s remaining wild spaces, and how fragile that diversity can be. While this particular species might not be destined for your garden, learning about it can deepen your appreciation for native plants everywhere.

Sometimes the best way to love a plant is to admire it from afar and work to protect the places where it naturally belongs. In the case of Luquillo Mountain clearweed, that might be the most loving thing we can do.

Liquillo Mountain Clearweed

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Hamamelididae

Order

Urticales

Family

Urticaceae Juss. - Nettle family

Genus

Pilea Lindl. - clearweed

Species

Pilea multicaulis Urb. - Liquillo Mountain clearweed

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