North America Native Plant

Pilo

Botanical name: Hedyotis mannii

USDA symbol: HEMA8

Life cycle: perennial

Habit: subshrub

Native status: Native to Hawaii  

Synonyms: Hedyotis mannii Fosberg var. cuspidata (HEMAC)  âš˜  Hedyotis mannii Fosberg var. munroi (HEMAM)  âš˜  Hedyotis mannii Fosberg var. scaposa (HEMAS)  âš˜  Hedyotis molokaiensis Fosberg (HEMO6)  âš˜  Hedyotis thyrsoidea Fosberg (HETH2)  âš˜  Hedyotis thyrsoidea Fosberg var. hillebrandii (HETHH)   

Pilo: A Critically Rare Hawaiian Native Worth Protecting If you’re passionate about Hawaiian native plants and conservation, you’ve probably never heard of pilo (Hedyotis mannii) – and there’s a very good reason for that. This incredibly rare shrub is one of Hawaii’s most endangered native plants, making it both fascinating ...

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) ⚘

Pilo: A Critically Rare Hawaiian Native Worth Protecting

If you’re passionate about Hawaiian native plants and conservation, you’ve probably never heard of pilo (Hedyotis mannii) – and there’s a very good reason for that. This incredibly rare shrub is one of Hawaii’s most endangered native plants, making it both fascinating and heartbreaking at the same time.

What Makes Pilo Special?

Pilo is a perennial shrub that’s as Hawaiian as it gets – it’s found nowhere else on Earth except the Hawaiian Islands. This multi-stemmed woody plant typically grows to less than 13-16 feet tall, though it can vary depending on environmental conditions. Like many Hawaiian natives, it belongs to a group of plants that evolved in isolation, making it truly unique.

Where Does Pilo Grow?

This rare beauty is endemic to Hawaii, meaning it naturally occurs only in the Hawaiian Islands. Unfortunately, its distribution is extremely limited, which contributes to its precarious conservation status.

The Conservation Reality

Here’s where things get serious: pilo has a Global Conservation Status of S1, which means it’s critically imperiled. In plain English? This plant is in serious trouble. With typically 5 or fewer known occurrences and very few remaining individuals (fewer than 1,000), pilo is teetering on the edge of extinction.

This rarity status means that if you’re interested in growing pilo, you need to be extremely careful about sourcing. Only work with reputable native plant nurseries or conservation organizations that can guarantee their plants come from ethically propagated stock – never from wild populations.

Should You Grow Pilo?

The short answer is: maybe, but only under the right circumstances. If you’re a dedicated native plant gardener in Hawaii with access to responsibly sourced material, growing pilo could be part of important conservation efforts. However, this isn’t a plant for casual gardeners or those new to Hawaiian natives.

What We Don’t Know (And Why That Matters)

Unfortunately, because pilo is so rare, many details about its growing requirements, wildlife benefits, and garden performance remain unknown or poorly documented. This includes:

  • Specific growing conditions and soil preferences
  • Pollinator relationships and wildlife benefits
  • Propagation methods and success rates
  • Detailed care requirements

This lack of information isn’t just an inconvenience for gardeners – it’s a conservation concern. The more we can learn about rare plants like pilo through careful cultivation and study, the better we can protect them.

Supporting Pilo Conservation

Even if you can’t grow pilo yourself, you can still support its conservation by:

  • Supporting Hawaiian native plant conservation organizations
  • Choosing other native Hawaiian plants for your garden
  • Learning about and sharing awareness of Hawaii’s rare native plants
  • Participating in habitat restoration efforts

The Bottom Line

Pilo represents both the incredible botanical diversity of Hawaii and the urgent need for plant conservation. While it may not be the right choice for most home gardens, understanding and appreciating rare natives like pilo helps us value the irreplaceable natural heritage of the Hawaiian Islands. If you’re serious about Hawaiian native plant conservation and have the right resources, growing pilo could be part of something much bigger than gardening – it could be part of saving a species.

Pilo

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Rubiales

Family

Rubiaceae Juss. - Madder family

Genus

Hedyotis L. - starviolet

Species

Hedyotis mannii Fosberg - pilo

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