North America Native Plant

Underwood’s Stopper

Botanical name: Eugenia underwoodii

USDA symbol: EUUN

Life cycle: perennial

Habit: shrub

Native status: Native to Puerto Rico  

Underwood’s Stopper: A Critically Endangered Puerto Rican Treasure Meet Underwood’s stopper (Eugenia underwoodii), one of Puerto Rico’s rarest native plants and a sobering reminder of how precious our natural heritage can be. If you’ve never heard of this elusive shrub, you’re not alone – with fewer than five known populations ...

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) ⚘

Underwood’s Stopper: A Critically Endangered Puerto Rican Treasure

Meet Underwood’s stopper (Eugenia underwoodii), one of Puerto Rico’s rarest native plants and a sobering reminder of how precious our natural heritage can be. If you’ve never heard of this elusive shrub, you’re not alone – with fewer than five known populations and likely under 1,000 individual plants remaining in the wild, this little-known member of the myrtle family is teetering on the edge of extinction.

What Makes This Plant So Special (And So Rare)

Underwood’s stopper is a perennial shrub that’s endemic to Puerto Rico, meaning it exists nowhere else on Earth. Like other shrubs, it’s a multi-stemmed woody plant that typically stays under 13-16 feet tall, with several stems growing from or near the ground. But here’s where things get serious: this plant has earned a Global Conservation Status of S1, which translates to Critically Imperiled – the most dire conservation category before extinction.

Where Does It Call Home?

This rare beauty is found only in Puerto Rico, where it clings to existence in just a handful of locations. The extreme rarity of Underwood’s stopper makes it especially vulnerable to environmental changes, habitat loss, and other threats that could push it toward extinction.

Should You Grow Underwood’s Stopper?

Here’s the honest truth: you almost certainly can’t – and probably shouldn’t try to – grow Underwood’s stopper in your garden. With so few plants left in the wild, this species simply isn’t available through normal nursery channels, nor should it be. Any cultivation efforts should be left to professional botanists and conservation programs working to save the species.

The Conservation Reality Check

When a plant reaches critically imperiled status, every individual becomes precious. Rather than seeking out this ultra-rare species for your garden, consider these more responsible alternatives:

  • Support conservation organizations working to protect Puerto Rico’s native flora
  • Choose other native Eugenia species that are more common and available
  • Focus on creating habitat for native plants and wildlife in your own region

Growing Conditions (For the Record)

While we can’t recommend growing Underwood’s stopper, understanding its needs helps us appreciate its ecological niche. As a Puerto Rican native, it would require tropical conditions similar to USDA hardiness zones 10-11. Like other tropical shrubs, it would likely prefer warm, humid conditions year-round – but again, this information is more academic than practical for home gardeners.

A Plant That Needs Our Protection, Not Our Gardens

Sometimes the most meaningful way to appreciate a plant is to leave it alone. Underwood’s stopper represents the fragility of island ecosystems and the urgent need for habitat conservation. Instead of trying to grow this critically endangered species, consider it a call to action: support native plant conservation, choose abundant native alternatives for your garden, and help protect the wild spaces where rare species like this one struggle to survive.

The story of Underwood’s stopper isn’t really about gardening – it’s about conservation, respect for nature’s rarity, and the sobering reality that some plants are simply too precious to pick up at the local nursery. And maybe that’s exactly as it should be.

Underwood’s Stopper

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

Myrtaceae Juss. - Myrtle family

Genus

Eugenia L. - stopper

Species

Eugenia underwoodii Britton - Underwood's stopper

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