North America Native Plant

Kesiamel

Botanical name: Osmoxylon oliveri

USDA symbol: OSOL

Life cycle: perennial

Habit: tree

Native status: Native to Pacific Basin excluding Hawaii  

Kesiamel: A Native Pacific Island Tree for Tropical Gardens If you’re lucky enough to garden in a tropical paradise, you might want to get acquainted with kesiamel (Osmoxylon oliveri), a fascinating native tree that’s perfectly at home in the warm, humid climates of the Pacific islands. This sturdy perennial has ...

Kesiamel: A Native Pacific Island Tree for Tropical Gardens

If you’re lucky enough to garden in a tropical paradise, you might want to get acquainted with kesiamel (Osmoxylon oliveri), a fascinating native tree that’s perfectly at home in the warm, humid climates of the Pacific islands. This sturdy perennial has been gracing the landscapes of Guam and Palau for generations, and it might just be the perfect addition to your tropical garden.

Where Does Kesiamel Come From?

Kesiamel is a true Pacific island native, naturally occurring in Guam and Palau within the broader Pacific Basin region (excluding Hawaii). This tree has evolved to thrive in the unique conditions of these tropical islands, making it an excellent choice for gardeners looking to incorporate authentic native plants into their landscapes.

What Does Kesiamel Look Like?

Don’t let the fancy botanical name fool you – kesiamel is simply a beautiful tropical tree that knows how to make a statement. As a member of the perennial woody plant family, this tree typically grows with a single, sturdy trunk and can reach impressive heights of 13 to 16 feet or more. Under certain environmental conditions, you might occasionally see it develop a more compact, multi-stemmed growth form, but the classic single-trunk tree shape is what you’ll usually encounter.

The tree belongs to the Araliaceae family, which gives it some distinctive characteristics that make it stand out in the tropical landscape. Its compound leaves create an attractive canopy that provides excellent shade – a real blessing in those hot Pacific island climates!

Is Kesiamel Right for Your Garden?

Here’s where things get interesting. Kesiamel is definitely not a plant for everyone, and that’s perfectly okay! This tree is specifically suited for:

  • Tropical and subtropical gardens in USDA hardiness zones 10-12
  • Locations with warm, humid climates year-round
  • Gardens where you want to showcase authentic Pacific island native plants
  • Landscapes that need a reliable shade tree
  • Areas where you want to support local ecosystem biodiversity

If you’re gardening outside of these tropical zones, kesiamel simply won’t be happy. This tree has evolved for specific climatic conditions and won’t tolerate cold temperatures or dry conditions.

Growing Kesiamel Successfully

The good news is that if you’re in the right climate zone, kesiamel can be relatively straightforward to grow. Here’s what this tropical beauty needs to thrive:

Climate Requirements

  • Warm temperatures year-round (USDA zones 10-12)
  • High humidity levels typical of tropical island climates
  • Protection from strong winds, though it can handle typical tropical breezes

Soil and Water Needs

  • Well-draining soil is essential – this tree doesn’t like to sit in waterlogged conditions
  • Regular watering during establishment, then moderate watering once established
  • Soil that mimics its natural Pacific island habitat works best

Planting and Care Tips

  • Plant in a location where it has room to reach its full mature height
  • Provide some protection from the strongest sun during the first year after planting
  • Mulch around the base to help retain moisture and regulate soil temperature
  • Prune minimally – this tree generally maintains its shape naturally

The Bottom Line on Kesiamel

Kesiamel is one of those plants that’s absolutely perfect for the right situation and completely wrong for everywhere else. If you’re gardening in Guam, Palau, or a similar tropical climate, this native tree offers you a chance to grow something truly authentic to your region. It provides reliable shade, supports local ecosystems, and connects your garden to the natural heritage of the Pacific islands.

However, if you’re outside of tropical zones 10-12, this isn’t the tree for you. Instead, look for native trees that are adapted to your specific climate and region – every area has its own wonderful native species that are perfectly suited to local conditions.

For those fortunate enough to garden in kesiamel’s native range, this tree represents a beautiful opportunity to create a landscape that’s both functional and deeply rooted in the natural history of your island home.

Kesiamel

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

Apiales

Family

Araliaceae Juss. - Ginseng family

Genus

Osmoxylon Miq.

Species

Osmoxylon oliveri Fosberg & Sachet - kesiamel

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