North America Native Plant

Ballou’s Melicope

Botanical name: Melicope balloui

USDA symbol: MEBA2

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Synonyms: Pelea balloui Rock (PEBA3)  âš˜  Pelea mannii Hillebr. p.p. (PEMA11)  âš˜  Pelea olowaluensis H. St. John (PEOL2)  âš˜  Pelea ukeleteensis H. St. John (PEUK)   

Ballou’s Melicope: A Critically Endangered Hawaiian Treasure Meet Ballou’s melicope (Melicope balloui), one of Hawaii’s rarest native shrubs and a plant that desperately needs our attention—not for your garden, but for its survival. This remarkable endemic species represents the unique botanical heritage of the Hawaiian Islands, but it’s teetering on ...

Rare plant alert!

Region: United States

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

Region: United States

Ballou’s Melicope: A Critically Endangered Hawaiian Treasure

Meet Ballou’s melicope (Melicope balloui), one of Hawaii’s rarest native shrubs and a plant that desperately needs our attention—not for your garden, but for its survival. This remarkable endemic species represents the unique botanical heritage of the Hawaiian Islands, but it’s teetering on the edge of extinction.

What Makes Ballou’s Melicope Special

Ballou’s melicope is a perennial shrub that belongs to the citrus family (Rutaceae). Like many Hawaiian natives, it evolved in isolation, developing characteristics found nowhere else on Earth. This multi-stemmed woody plant typically grows less than 13-16 feet tall, making it a medium-sized shrub in its native habitat.

You might also encounter this plant in scientific literature under its former names, including Pelea balloui Rock, Pelea mannii, Pelea olowaluensis, or Pelea ukeleteensis—all synonyms that reflect the complex botanical history of Hawaiian flora classification.

Where It Calls Home

This rare beauty is found exclusively in Hawaii, where it clings to existence in its native island ecosystem. As an endemic species, Ballou’s melicope evolved specifically to thrive in Hawaiian conditions and plays an irreplaceable role in the islands’ ecological web.

A Plant in Crisis

Here’s where things get serious: Ballou’s melicope has a Global Conservation Status of S1, meaning it’s critically imperiled. With typically five or fewer occurrences and very few remaining individuals (fewer than 1,000), this species is officially listed as Endangered in the United States. Every individual plant matters for the survival of this species.

Should You Grow Ballou’s Melicope?

The short answer is: probably not, unless you’re working with a legitimate conservation program. Given its critically endangered status, Ballou’s melicope should only be cultivated with responsibly sourced material obtained through proper conservation channels. This isn’t a plant for casual gardening—it’s a species fighting for survival.

If you’re passionate about Hawaiian native plants and conservation, consider:

  • Supporting Hawaiian plant conservation organizations
  • Volunteering with native habitat restoration projects
  • Growing other less endangered Hawaiian natives in your garden
  • Advocating for habitat protection in Hawaii

The Bigger Picture

While we can’t provide growing tips for this critically endangered species, we can appreciate its importance. Ballou’s melicope represents thousands of years of evolutionary adaptation to Hawaii’s unique environment. Its survival depends on protecting remaining wild populations and supporting professional conservation efforts.

Every endangered plant tells a story about habitat loss, invasive species, and the delicate balance of island ecosystems. By learning about species like Ballou’s melicope, we become better advocates for the native plants that still have a chance to thrive in our gardens and wild spaces.

Instead of trying to grow this rare treasure, consider supporting its conservation and choosing other native plants that can safely grace your garden while supporting local ecosystems. Sometimes the best way to love a plant is to let the experts handle its care while we protect the places where it belongs.

Ballou’s Melicope

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

Sapindales

Family

Rutaceae Juss. - Rue family

Genus

Melicope (J.R. Forst. & G. Forst.) T.G. Hartley & B.C. Stone - melicope

Species

Melicope balloui (Rock) T.G. Hartley & B.C. Stone - Ballou's melicope

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