North America Native Plant

Maricao River Hempvine

Botanical name: Mikania stevensiana

USDA symbol: MIST6

Life cycle: perennial

Habit: vine

Native status: Native to Puerto Rico  

Maricao River Hempvine: Puerto Rico’s Critically Endangered Hidden Gem Meet the Maricao River hempvine (Mikania stevensiana), one of Puerto Rico’s most elusive botanical treasures. This isn’t your typical garden center find – in fact, you’d be incredibly lucky (and frankly, shouldn’t even try) to encounter this extremely rare native plant ...

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) ⚘

Maricao River Hempvine: Puerto Rico’s Critically Endangered Hidden Gem

Meet the Maricao River hempvine (Mikania stevensiana), one of Puerto Rico’s most elusive botanical treasures. This isn’t your typical garden center find – in fact, you’d be incredibly lucky (and frankly, shouldn’t even try) to encounter this extremely rare native plant in the wild.

What Makes This Plant So Special?

The Maricao River hempvine is a perennial forb herb, meaning it’s a soft-stemmed plant that comes back year after year without developing woody tissue like trees and shrubs. Think of it as nature’s version of a low-key wildflower, though calling it low-key might be an understatement given its rarity!

As a member of the sunflower family, this little herb lacks the significant woody growth you’d see in bushes or trees. Instead, it keeps its growing points (called perennating buds) right at or below ground level, playing it safe Puerto Rican style.

Where Does It Call Home?

This plant is a true Puerto Rican endemic, meaning it exists nowhere else on Earth except on this beautiful Caribbean island. Its entire world consists of Puerto Rico’s unique ecosystems, making it incredibly precious from a biodiversity standpoint.

The Conservation Reality Check

Here’s where things get serious, folks. The Maricao River hempvine has a Global Conservation Status of S1, which translates to Critically Imperiled. This means:

  • Typically 5 or fewer known locations exist
  • Very few individuals remain (likely fewer than 1,000 plants total)
  • The species faces extreme risk of extinction

When a plant reaches S1 status, it’s essentially hanging on by a thread. Every single individual plant becomes incredibly important for the species’ survival.

Can I Grow This in My Garden?

The short answer? Please don’t try. With so few individuals left in the wild, attempting to collect or grow Maricao River hempvine could contribute to pushing this species toward extinction. Even well-meaning gardeners can inadvertently harm critically endangered species.

This plant’s facultative wetland status means it can grow in both wet and dry conditions, but its specific growing requirements and habitat needs are likely very specialized – which is often why plants become so rare in the first place.

How You Can Actually Help

Instead of trying to grow this rare beauty, consider these meaningful alternatives:

  • Support Puerto Rican botanical gardens and conservation organizations
  • Choose other native Puerto Rican plants that aren’t critically endangered
  • Donate to plant conservation efforts
  • Spread awareness about Puerto Rico’s unique flora

The Bigger Picture

Plants like the Maricao River hempvine remind us that our world is full of incredible species hanging on in small, often overlooked corners of the Earth. Puerto Rico, despite its relatively small size, harbors numerous endemic species found nowhere else.

While we can’t bring this particular plant into our gardens, we can appreciate its existence and work to protect the wild spaces where it still survives. Sometimes the best thing we can do for a plant is simply let it be – and ensure that the places it calls home remain protected for future generations.

The next time you’re planning your native garden, remember the Maricao River hempvine and choose abundant native species instead. Your local ecosystem will thank you, and you’ll be doing your part to keep the pressure off our planet’s most vulnerable plants.

Maricao River Hempvine

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

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Mikania Willd. - hempvine

Species

Mikania stevensiana Britton - Maricao River hempvine

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