North America Native Plant

Urban’s Mimosa

Botanical name: Mimosa quadrivalvis var. urbaniana

USDA symbol: MIQUU

Life cycle: perennial

Habit: vine

Native status: Native to Puerto Rico  

Synonyms: Morongia portoricensis (Urb.) Britton (MOPO)  âš˜  Schrankia portoricensis Urb. (SCPO3)   

Urban’s Mimosa: A Critically Rare Puerto Rican Native Meet Urban’s mimosa (Mimosa quadrivalvis var. urbaniana), one of Puerto Rico’s most elusive native plants. This perennial herb belongs to the fascinating mimosa family, but don’t expect to find it at your local garden center – this little plant is rarer than ...

Rare plant alert!

Region: Conservation status by state

Status: S5T1: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is 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) ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

Urban’s Mimosa: A Critically Rare Puerto Rican Native

Meet Urban’s mimosa (Mimosa quadrivalvis var. urbaniana), one of Puerto Rico’s most elusive native plants. This perennial herb belongs to the fascinating mimosa family, but don’t expect to find it at your local garden center – this little plant is rarer than a unicorn in your backyard!

What Makes Urban’s Mimosa Special

Urban’s mimosa is what botanists call a forb herb, meaning it’s a soft-stemmed perennial plant without the woody tissue you’d find in shrubs or trees. Think of it as nature’s gentle groundcover option, designed to live close to the earth with its growing points tucked safely at or below ground level.

This plant is also known by its scientific synonyms Morongia portoricensis and Schrankia portoricensis, names that reflect its deep roots in Puerto Rican botanical history.

Where Does It Call Home

Urban’s mimosa is endemic to Puerto Rico, meaning this island paradise is the only place on Earth where this plant naturally occurs. It’s a true Puerto Rican native that has evolved specifically for the unique conditions found on the island.

The Conservation Reality Check

Here’s where we need to have a serious conversation. Urban’s mimosa carries a Global Conservation Status of S5T1, which puts it in the critically imperiled category. This classification means the plant faces an extremely high risk of extinction, with very few known populations remaining in the wild.

What this means for gardeners: This isn’t your typical let’s add it to the garden situation. If you’re interested in this plant, you’re essentially talking about participating in conservation efforts rather than casual gardening.

Should You Grow Urban’s Mimosa

The short answer is: probably not, and here’s why. With such a critical conservation status, any cultivation should be:

  • Part of official conservation programs
  • Done with properly sourced, legally obtained plant material
  • Coordinated with botanical institutions or conservation organizations
  • Focused on species preservation rather than ornamental use

For most home gardeners, supporting Puerto Rican native plant conservation is better achieved by growing other native Puerto Rican species that aren’t critically endangered.

Growing Conditions and Care

Unfortunately, specific growing requirements for Urban’s mimosa aren’t well-documented in standard horticultural literature – partly because of its extreme rarity. As a Puerto Rican native, it would likely prefer:

  • Tropical to subtropical conditions (similar to USDA zones 11-12)
  • The climate conditions native to Puerto Rico
  • Growing conditions that mimic its natural Puerto Rican habitat

However, without more specific habitat data, providing detailed care instructions would be speculation.

Alternative Native Options

If you’re passionate about Puerto Rican native plants, consider exploring other native species that aren’t critically endangered. Puerto Rico has a rich flora with many beautiful native options that can thrive in cultivation while supporting local ecosystems.

Working with local Puerto Rican botanical gardens, native plant societies, or conservation organizations can help you discover wonderful native alternatives that won’t put additional pressure on critically rare species.

The Bottom Line

Urban’s mimosa represents the delicate beauty of Puerto Rico’s unique flora, but it’s also a reminder of how precious and vulnerable our native plant heritage can be. Rather than trying to grow this critically rare species, consider it an ambassador for the importance of plant conservation and habitat protection.

Sometimes the best way to appreciate a plant is to support its conservation in the wild, ensuring future generations might have the chance to encounter this remarkable little herb in its natural Puerto Rican home.

Urban’s Mimosa

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

Mimosa L. - sensitive plant

Species

Mimosa quadrivalvis L. - fourvalve mimosa

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