North America Native Plant

Merrill’s Polyalthia

Botanical name: Polyalthia merrillii

USDA symbol: POME

Life cycle: perennial

Habit: tree

Native status: Native to Pacific Basin excluding Hawaii  

Merrill’s Polyalthia: A Rare Pacific Island Native Tree Worth Knowing If you’re looking for a unique native tree with Pacific Island heritage, Merrill’s polyalthia (Polyalthia merrillii) might just pique your interest. This perennial tree species brings a touch of tropical authenticity to gardens in its native range, though you won’t ...

Merrill’s Polyalthia: A Rare Pacific Island Native Tree Worth Knowing

If you’re looking for a unique native tree with Pacific Island heritage, Merrill’s polyalthia (Polyalthia merrillii) might just pique your interest. This perennial tree species brings a touch of tropical authenticity to gardens in its native range, though you won’t find much chatter about it in typical gardening circles – and there’s a good reason for that.

Where Does Merrill’s Polyalthia Call Home?

This native beauty hails from the Pacific Basin, specifically making its home in Guam and Palau. It’s one of those special plants that truly belongs to its place, having evolved alongside the unique ecosystems of these Pacific islands.

What You’re Getting: A True Tree

Merrill’s polyalthia is what botanists call a proper tree – meaning it’s a woody, perennial plant with a single trunk that typically grows taller than 13 to 16 feet. Like many trees, it can sometimes develop multiple stems or stay shorter than usual depending on environmental conditions, but generally, you’re looking at a substantial addition to your landscape.

The Reality Check: Information is Scarce

Here’s where things get interesting (and a bit challenging). While Merrill’s polyalthia is a legitimate native species, detailed information about its specific growing requirements, appearance, and garden performance is remarkably limited. This isn’t uncommon with native plants from smaller Pacific islands – they simply haven’t received the same horticultural attention as their mainland cousins.

Should You Plant It?

The honest answer? It depends on your situation and goals:

  • If you’re in Guam or Palau: This could be a wonderful way to support native biodiversity and connect with your local ecosystem
  • If you’re elsewhere: You might want to consider better-documented native alternatives for your specific region
  • If you’re a plant collector: The rarity of information makes this an intriguing challenge, though sourcing may be difficult

Growing Conditions: Educated Guesses

Since specific growing information is limited, we can make some educated assumptions based on its native habitat:

  • Likely prefers tropical or subtropical conditions
  • Probably enjoys well-draining soil
  • May need protection from strong winds (island native adaptation)
  • Likely requires consistent moisture but not waterlogged conditions

The Bottom Line

Merrill’s polyalthia represents one of those fascinating native plants that deserves more attention and research. If you’re in its native range and can source it responsibly, it could be a meaningful addition to native plant restoration efforts. However, for most gardeners, the lack of detailed growing information makes it a challenging choice.

Consider this plant a reminder of how much we still have to learn about our native flora – and perhaps an inspiration to support botanical research and conservation efforts in Pacific island ecosystems.

Merrill’s Polyalthia

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Magnoliidae

Order

Magnoliales

Family

Annonaceae Juss. - Custard-apple family

Genus

Polyalthia Blume - polyalthia

Species

Polyalthia merrillii Kaneh. - Merrill's polyalthia

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