North America Native Plant

River Cyrtandra

Botanical name: Cyrtandra rivularis

USDA symbol: CYRI3

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Synonyms: Cyrtandra villosa H. St. John & Storey (CYVI5)   

River Cyrtandra: A Rare Hawaiian Native Worth Protecting in Your Garden Meet the river cyrtandra (Cyrtandra rivularis), a critically endangered Hawaiian native that deserves a special place in every tropical gardener’s heart. This charming shrub isn’t just another pretty face in the plant world – it’s a conservation success story ...

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) ⚘

River Cyrtandra: A Rare Hawaiian Native Worth Protecting in Your Garden

Meet the river cyrtandra (Cyrtandra rivularis), a critically endangered Hawaiian native that deserves a special place in every tropical gardener’s heart. This charming shrub isn’t just another pretty face in the plant world – it’s a conservation success story waiting to happen in your backyard.

What Makes River Cyrtandra Special?

River cyrtandra is a perennial shrub that typically grows as a multi-stemmed woody plant, usually staying under 13-16 feet tall. True to its name, this native Hawaiian beauty naturally thrives along streams and in wet forest areas throughout the Hawaiian Islands. You might also see it listed under its scientific synonym, Cyrtandra villosa H. St. John & Storey, but don’t let the fancy names fool you – this is one approachable plant.

Where Does River Cyrtandra Call Home?

This endemic species is found exclusively in Hawaii, where it has evolved over thousands of years to perfectly fit into the islands’ unique ecosystem. Unfortunately, habitat loss and other pressures have made river cyrtandra critically imperiled, with typically fewer than 1,000 individuals remaining in the wild.

Why Your Garden Needs This Rare Beauty

Here’s the thing about river cyrtandra – it’s not just a plant, it’s a conservation opportunity. By growing this species (with responsibly sourced material, of course), you’re participating in preserving Hawaii’s unique botanical heritage. Plus, it brings some serious aesthetic appeal to shaded garden spaces with its attractive foliage and delicate tubular flowers that typically appear in white or pale hues.

Perfect for these garden types:

  • Native Hawaiian restoration gardens
  • Tropical shade gardens
  • Conservation-focused landscapes
  • Understory plantings in humid environments

Growing Conditions: Keep It Happy and Humid

River cyrtandra is suited for USDA hardiness zones 10-12, making it a tropical-only garden resident. Think of it as Hawaii’s answer to the perfect shade plant – it loves:

  • Shade to partial shade conditions
  • High humidity environments
  • Consistently moist, well-draining soil
  • Protection from strong winds
  • Organic-rich growing medium

Planting and Care Tips

The key to success with river cyrtandra is recreating its natural habitat as closely as possible. Plant it in a sheltered spot where it gets filtered light, similar to a forest understory. Keep the soil consistently moist but never waterlogged – think jungle floor rather than swamp.

Regular applications of organic matter will keep your river cyrtandra thriving, and don’t forget that consistent humidity is crucial. If you’re growing it outside of its natural range, consider grouping it with other moisture-loving plants to create a beneficial microclimate.

A Important Conservation Note

Here’s where we need to have a serious conversation: river cyrtandra has a Global Conservation Status of S1, meaning it’s critically imperiled. While we absolutely encourage growing this species to support conservation efforts, it’s crucial that you source plants only from reputable nurseries that propagate from legally and ethically obtained material. Never collect from wild populations – every plant in nature counts toward this species’ survival.

Supporting Native Ecosystems

Beyond its conservation value, river cyrtandra plays an important role in supporting native Hawaiian wildlife. Its flowers attract native insects and potentially native birds, making it a valuable addition to any ecosystem-focused garden design.

By choosing river cyrtandra for your tropical garden, you’re not just adding a beautiful plant – you’re becoming part of the solution for preserving Hawaii’s irreplaceable native flora. Just remember: source responsibly, plant thoughtfully, and enjoy knowing you’re helping keep this rare beauty around for future generations to discover.

River Cyrtandra

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

Scrophulariales

Family

Gesneriaceae Rich. & Juss. - Gesneriad family

Genus

Cyrtandra J.R. Forst. & G. Forst. - cyrtandra

Species

Cyrtandra rivularis H. St. John & Storey - river cyrtandra

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