North America Non-native Plant

Rhynchosia Usambarensis

Botanical name: Rhynchosia usambarensis

USDA symbol: RHUS2

Native status: Not native but doesn't reproduce and persist in the wild

Rhynchosia usambarensis: The Mysterious Legume from East Africa If you’ve stumbled across the name Rhynchosia usambarensis in your plant research, you’re probably wondering what exactly this species is and whether it belongs in your garden. Well, you’re in for a bit of a mystery! This lesser-known member of the legume ...

Rhynchosia usambarensis: The Mysterious Legume from East Africa

If you’ve stumbled across the name Rhynchosia usambarensis in your plant research, you’re probably wondering what exactly this species is and whether it belongs in your garden. Well, you’re in for a bit of a mystery! This lesser-known member of the legume family is one of those plants that keeps botanical secrets close to its chest.

What We Know (And Don’t Know) About This Elusive Plant

Rhynchosia usambarensis belongs to the Rhynchosia genus, a group of flowering plants in the pea family (Fabaceae). The species name usambarensis gives us a tantalizing clue about its origins – it likely hails from the Usambara Mountains region of Tanzania in East Africa. However, beyond this geographical hint, reliable information about this particular species is remarkably scarce in cultivation databases and gardening literature.

Geographic Distribution and Native Status

While we can make educated guesses based on the species name that this plant originates from East African mountain regions, particularly around Tanzania, the exact native range and current distribution remain unclear in available sources. This lack of documentation suggests it may be a rarely studied or regionally endemic species.

Should You Grow Rhynchosia usambarensis?

Here’s where things get tricky. With so little information available about this species’ growing requirements, invasive potential, conservation status, or even basic characteristics like size and appearance, it’s difficult to make cultivation recommendations. If you’re considering growing this plant, here are some important considerations:

  • Availability is likely extremely limited in the nursery trade
  • Growing requirements are largely unknown
  • Climate suitability for your region cannot be determined
  • Conservation status is unclear

Alternative Options for Your Garden

If you’re interested in legumes with African origins or similar characteristics, consider exploring better-documented species within the Rhynchosia genus or related genera that are readily available and well-suited to cultivation. Many native legumes can provide similar ecological benefits while being much easier to grow successfully.

The Bottom Line

Rhynchosia usambarensis remains something of an enigma in the gardening world. Without reliable information about its growth habits, environmental needs, or conservation status, it’s not a plant we can confidently recommend for home cultivation. If you’re drawn to unique or rare plants, focus on species with well-documented growing requirements and known availability through reputable sources.

Sometimes the most responsible approach to mysterious plants is to appreciate them from afar while supporting conservation efforts in their native habitats. Who knows? Maybe future botanical research will unlock the secrets of this intriguing East African species and make it more accessible to gardeners worldwide.

Rhynchosia Usambarensis

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

Rhynchosia Lour. - snoutbean

Species

Rhynchosia usambarensis Taub.

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