North America Non-native Plant

Horseeye Bean

Botanical name: Mucuna sloanei var. persericea

USDA symbol: MUSLP

Life cycle: perennial

Habit: vine

Native status: Probably non-native, reproduces and persists in the wild in Hawaii  

Horseeye Bean: A Rare Hawaiian Treasure Not for Your Garden Meet the horseeye bean (Mucuna sloanei var. persericea), a plant so rare that most gardeners will never encounter it—and that’s probably for the best. This perennial herb holds a special place in Hawaii’s botanical landscape, but it’s definitely not your ...

Rare plant alert!

Region: United States

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. ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Horseeye Bean: A Rare Hawaiian Treasure Not for Your Garden

Meet the horseeye bean (Mucuna sloanei var. persericea), a plant so rare that most gardeners will never encounter it—and that’s probably for the best. This perennial herb holds a special place in Hawaii’s botanical landscape, but it’s definitely not your typical garden center find.

What Makes the Horseeye Bean Special?

The horseeye bean is a fascinating forb—essentially a non-woody plant that dies back to ground level but returns year after year. Unlike shrubs or trees, this perennial lacks significant woody tissue above ground, making it more herbaceous in nature. It’s part of the legume family, which means it likely has those characteristic bean-like pods that give it its common name.

Where Does It Call Home?

Currently, you’ll only find the horseeye bean in Hawaii, where it’s believed to be a non-native species that was introduced at some point in history. While it has made Hawaii its home, this plant’s journey to the islands remains somewhat of a botanical mystery.

Why You Shouldn’t Plant This Beauty

Here’s where things get serious: the horseeye bean is endangered in the United States. With a rarity status that puts it in critical conservation territory, this plant is far too precious for casual gardening. Think of it as the botanical equivalent of a rare butterfly—better admired from afar and left to conservation professionals.

If you’re absolutely determined to work with rare Hawaiian plants, here’s what you need to know:

  • Only source from certified conservation programs
  • Work with botanical institutions or native plant societies
  • Understand that permits may be required
  • Focus on habitat restoration rather than ornamental gardening

Better Alternatives for Your Garden

Instead of seeking out this endangered species, consider these more sustainable options for your landscape:

  • Other native Hawaiian legumes that are more readily available
  • Common native beans and legumes appropriate to your region
  • Non-rare Mucuna species that offer similar aesthetics without conservation concerns

Supporting Conservation Efforts

The best way to help the horseeye bean is to support organizations working to protect Hawaii’s rare plants. Consider donating to or volunteering with:

  • Local botanical gardens with conservation programs
  • Native plant societies in Hawaii
  • University research programs studying rare species

The Bottom Line

While the horseeye bean is undoubtedly a remarkable plant with its own ecological story, it’s not destined for home gardens. Its endangered status means it needs protection, not propagation by amateur gardeners. Sometimes the most loving thing we can do for a plant is to admire it from afar and let the experts handle its care.

For your own garden, there are countless other wonderful native options that won’t put rare species at risk. Save the horseeye bean appreciation for nature documentaries and botanical garden visits—your local ecosystem will thank you for choosing more appropriate alternatives.

Horseeye Bean

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

Mucuna Adans. - mucuna

Species

Mucuna sloanei Fawc. & Rendle - horseeye bean

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