North America Native Plant

Quina Roja

Botanical name: Antirhea obtusifolia

USDA symbol: ANOB2

Life cycle: perennial

Habit: shrub

Native status: Native to Puerto Rico  

Synonyms: Stenostomum obtusifolium (Urb.) Britton & P. Wilson (STOB3)   

Quina Roja: A Rare Native Puerto Rican Shrub Worth Knowing If you’re passionate about native plants and happen to garden in Puerto Rico, you might be curious about some of the island’s lesser-known botanical treasures. Enter quina roja (Antirhea obtusifolia), a native shrub that’s as mysterious as it is rare. ...

Rare plant alert!

Region: Conservation status by state

Status: S2?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘

Quina Roja: A Rare Native Puerto Rican Shrub Worth Knowing

If you’re passionate about native plants and happen to garden in Puerto Rico, you might be curious about some of the island’s lesser-known botanical treasures. Enter quina roja (Antirhea obtusifolia), a native shrub that’s as mysterious as it is rare. While this plant won’t be found at your typical garden center, it represents an important part of Puerto Rico’s natural heritage that deserves our attention and protection.

What is Quina Roja?

Quina roja is a perennial shrub native exclusively to Puerto Rico. Like most shrubs, it’s a multi-stemmed woody plant that typically grows less than 13 to 16 feet tall, with several stems emerging from or near the ground. You might also see it referenced by its synonym, Stenostomum obtusifolium, in older botanical literature.

This plant belongs to Puerto Rico’s unique flora, found nowhere else in the world. It’s what botanists call an endemic species – a true island original that evolved specifically in Puerto Rican ecosystems.

Where Does Quina Roja Grow?

Quina roja is found only in Puerto Rico, making it a true island endemic. Its natural distribution is limited to specific habitats within the island, contributing to its rarity and conservation concern.

A Plant of Conservation Concern

Here’s something important every gardener should know: quina roja has a Global Conservation Status of S2?, which indicates it’s considered rare and potentially vulnerable. While the exact threat level is somewhat undefined (hence the question mark), this designation suggests the species needs our attention and protection.

If you’re interested in growing this plant, it’s crucial to source it responsibly. Never collect plants from the wild, and only obtain specimens from reputable native plant nurseries that propagate their stock ethically. Better yet, consider supporting conservation efforts that protect the natural habitats where quina roja grows.

Growing Conditions and Garden Potential

What we do know about quina roja’s preferences comes from its wetland status. In the Caribbean region, it’s classified as a Facultative Wetland species, which means it usually grows in wetlands but can tolerate some non-wetland conditions. This suggests it might appreciate:

  • Consistently moist soil conditions
  • Areas with good water retention
  • Possibly some tolerance for occasional drier periods

For Puerto Rican gardeners working in tropical conditions (roughly USDA zones 11-12), this adaptability to both wet and somewhat drier conditions could make it a valuable addition to rain gardens or naturalized landscapes that experience seasonal moisture variations.

Why Consider Quina Roja for Your Garden?

While information about quina roja’s specific ornamental qualities is limited, there are compelling reasons to consider this rare native:

  • Conservation value: Growing native plants helps preserve genetic diversity and supports local ecosystems
  • Adaptation: As a Puerto Rican native, it’s naturally suited to local climate conditions
  • Uniqueness: You’d be growing something truly special – a plant found nowhere else on Earth
  • Educational opportunity: It’s a conversation starter about native plant conservation

The Reality Check

Let’s be honest – quina roja isn’t going to be the easiest plant to find or grow. Its rarity means there’s limited cultivation experience to draw from, and you’re unlikely to find detailed care instructions or troubleshooting guides. This makes it more suitable for experienced native plant enthusiasts rather than beginning gardeners.

If you’re new to native gardening in Puerto Rico, you might want to start with more common native species that are better documented and easier to source. As you build experience with Puerto Rican natives, you can work your way up to conservation challenges like quina roja.

Supporting Conservation

Sometimes the best way to grow a rare plant is to support its conservation in the wild. Consider connecting with local botanical gardens, native plant societies, or conservation organizations in Puerto Rico that work to protect endemic species like quina roja. Your support can help ensure future generations will have the opportunity to appreciate this unique shrub.

Whether or not you ever get the chance to grow quina roja yourself, knowing about plants like this enriches our understanding of the incredible botanical diversity that islands like Puerto Rico harbor. Every endemic species tells a story of evolution, adaptation, and the intricate connections that make ecosystems work.

Quina Roja

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

Rubiales

Family

Rubiaceae Juss. - Madder family

Genus

Antirhea Comm. ex Juss. - quina

Species

Antirhea obtusifolia Urb. - quina roja

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