North America Native Plant

Caroline Cleistanthus

Botanical name: Cleistanthus carolinianus

USDA symbol: CLCA18

Life cycle: perennial

Habit: shrub

Native status: Native to Pacific Basin excluding Hawaii  

Caroline Cleistanthus: A Pacific Island Native Worth Knowing Meet Caroline cleistanthus (Cleistanthus carolinianus), a charming Pacific island native that might just be the hidden gem your tropical garden has been waiting for. While this perennial shrub isn’t exactly a household name in gardening circles, it carries the distinction of being ...

Caroline Cleistanthus: A Pacific Island Native Worth Knowing

Meet Caroline cleistanthus (Cleistanthus carolinianus), a charming Pacific island native that might just be the hidden gem your tropical garden has been waiting for. While this perennial shrub isn’t exactly a household name in gardening circles, it carries the distinction of being authentically native to the Pacific Basin—specifically calling Guam and Palau home.

What Makes Caroline Cleistanthus Special?

Caroline cleistanthus is a multi-stemmed woody shrub that typically stays under 13-16 feet tall, though it can occasionally stretch taller or grow with a single stem depending on its growing conditions. As a true Pacific Basin native (excluding Hawaii), this plant represents the authentic flora of Guam and Palau, making it a meaningful choice for gardeners in these regions who want to celebrate their local plant heritage.

The Reality Check: Limited Information Available

Here’s where we need to be honest—Caroline cleistanthus is somewhat of a mystery plant when it comes to detailed cultivation information. Unlike popular native plants that have been extensively studied and grown, this Pacific island endemic hasn’t received much attention in horticultural literature. This means if you’re considering growing it, you’ll be part of a select group of adventurous gardeners.

Should You Plant Caroline Cleistanthus?

If you’re gardening in Guam or Palau, there are compelling reasons to consider this native shrub:

  • It’s authentically native to your region
  • Supporting native plants helps preserve local ecosystems
  • You’ll be growing something truly unique
  • Native plants are typically well-adapted to local conditions

However, the lack of detailed growing information means you’ll need to be prepared for some trial and error.

What We Know About Growing Conditions

Since Caroline cleistanthus is native to Guam and Palau, we can make some educated guesses about its preferences:

  • Likely thrives in tropical conditions
  • Probably enjoys warm, humid climates year-round
  • May be adapted to island soil conditions
  • Could be tolerant of salt spray and coastal conditions

Garden Design Possibilities

As a shrub that can grow to 13-16 feet, Caroline cleistanthus could potentially serve as:

  • A privacy screen or natural fence
  • A specimen plant in native plant gardens
  • Part of a mixed native shrub border
  • A conservation planting in restoration projects

The Bottom Line

Caroline cleistanthus represents an opportunity to grow something truly special—a plant that belongs specifically to the Pacific islands of Guam and Palau. While the lack of detailed cultivation information makes it a plant for adventurous gardeners rather than beginners, choosing native species like this one supports local ecosystems and celebrates regional botanical heritage.

If you’re in Guam or Palau and decide to try growing Caroline cleistanthus, consider reaching out to local native plant societies, botanical gardens, or conservation groups. They may have practical experience with this species and can offer valuable growing tips based on local knowledge.

Sometimes the most rewarding garden plants are the ones that challenge us to learn something new—and Caroline cleistanthus certainly fits that description.

Caroline Cleistanthus

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

Euphorbiales

Family

Euphorbiaceae Juss. - Spurge family

Genus

Cleistanthus Hook. f. ex Planch.

Species

Cleistanthus carolinianus Jabl. - Caroline cleistanthus

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