North America Native Plant

Smooth Yellow Nicker

Botanical name: Caesalpinia culebrae

USDA symbol: CACU10

Life cycle: perennial

Habit: vine

Native status: Native to Puerto Rico  

Smooth Yellow Nicker: A Critically Endangered Caribbean Treasure Meet the smooth yellow nicker (Caesalpinia culebrae), one of Puerto Rico’s rarest botanical gems. This perennial climbing plant represents both the incredible diversity of Caribbean flora and the urgent need for plant conservation in our modern world. What Makes This Plant Special? ...

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) ⚘

Smooth Yellow Nicker: A Critically Endangered Caribbean Treasure

Meet the smooth yellow nicker (Caesalpinia culebrae), one of Puerto Rico’s rarest botanical gems. This perennial climbing plant represents both the incredible diversity of Caribbean flora and the urgent need for plant conservation in our modern world.

What Makes This Plant Special?

The smooth yellow nicker is a fascinating twining climber that belongs to the legume family. With stems that can be either woody or herbaceous, this perennial plant has adapted to life as a vine, using its relatively long stems to climb and spread through its native habitat.

What truly sets this plant apart, however, isn’t just its growth habit—it’s its incredible rarity. Caesalpinia culebrae holds a Global Conservation Status of S1, meaning it’s critically imperiled. To put this in perspective, there are typically only five or fewer known locations where this plant exists, with fewer than 1,000 individual plants remaining in the wild.

Native Range and Distribution

This remarkable species is endemic to Puerto Rico, meaning it exists naturally nowhere else on Earth. The smooth yellow nicker represents a unique piece of Puerto Rican biodiversity that has evolved specifically within the island’s ecosystems over thousands of years.

A Plant Not for Every Garden

Here’s where we need to have a serious conversation about conservation. While many native plants make excellent garden additions, the smooth yellow nicker falls into a very different category. With its critically imperiled status, this isn’t a plant you’ll find at your local nursery, nor should you actively seek it out for your landscape.

Conservation Considerations

If you’re passionate about Puerto Rican native plants and conservation, here’s what you should know:

  • Extreme rarity: With so few individuals left, every plant matters for species survival
  • Responsible sourcing: Any cultivation should only occur through legitimate conservation programs
  • Professional involvement: Work with botanical gardens, conservation organizations, or researchers
  • Habitat protection: Supporting habitat conservation may be more impactful than individual cultivation

Growing Conditions (For Conservation Purposes Only)

While specific growing requirements for Caesalpinia culebrae aren’t well-documented due to its rarity, we can make educated assumptions based on its Puerto Rican origins:

  • Climate: Likely thrives in tropical conditions similar to USDA zones 10-11
  • Growth habit: Needs support structures for its climbing nature
  • Soil: Specific preferences unknown but likely adapted to Caribbean soil conditions

Alternative Native Climbing Plants

If you’re interested in supporting Caribbean biodiversity in your garden, consider these more common Puerto Rican native climbers that won’t impact wild populations:

  • Other Caesalpinia species that are more common
  • Native passion vines (Passiflora species)
  • Indigenous morning glories

How You Can Help

While you might not be able to grow this rare beauty in your backyard, you can still make a difference:

  • Support Puerto Rican botanical gardens and conservation organizations
  • Choose other native Puerto Rican plants for your garden
  • Spread awareness about Caribbean plant conservation
  • Contribute to habitat preservation efforts

The Bigger Picture

The smooth yellow nicker serves as a powerful reminder of how precious and fragile our plant diversity can be. While we can’t all have this rare climber in our gardens, we can honor its existence by making thoughtful choices about the plants we do grow and by supporting conservation efforts that protect species like this one.

Sometimes the most beautiful way to appreciate a plant is to ensure it continues to exist in its natural habitat for future generations to discover and protect.

Smooth Yellow Nicker

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

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Caesalpinia L. - nicker

Species

Caesalpinia culebrae (Britton & P. Wilson) Alain - smooth yellow nicker

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