Native Plants

Hawai’i Phyllostegia

Phyllostegia floribunda

USDA symbol: PHFL6

perennial subshrub

Hawaii: native

If you’re passionate about Hawaiian native plants and conservation gardening, you may have heard whispers about the elusive Hawai’i phyllostegia (Phyllostegia floribunda). This remarkable native shrub represents both the beauty and fragility of Hawaii’s endemic flora, making it a plant that deserves our attention and respect. Hawai’i phyllostegia is a ...

Hawai’i Phyllostegia may be listed as rare in your area.
Global Conservation Status

Status: S1 | Critically imperiled: Typically 5 or fewer occurrences or under 1,000 remaining individuals.

United States

Status: Endangered | Endangered. In danger of extinction throughout all or a significant portion of its range.

Hawai’i Phyllostegia: A Rare Jewel of Hawaiian Native Gardens

If you’re passionate about Hawaiian native plants and conservation gardening, you may have heard whispers about the elusive Hawai’i phyllostegia (Phyllostegia floribunda). This remarkable native shrub represents both the beauty and fragility of Hawaii’s endemic flora, making it a plant that deserves our attention and respect.

What Makes Hawai’i Phyllostegia Special?

Hawai’i phyllostegia is a perennial shrub that belongs to Hawaii’s unique botanical heritage. As a member of the mint family, this native beauty typically grows as a multi-stemmed woody plant, usually staying under 13-16 feet in height. What sets it apart are its charming small flowers that range from white to pale purple, arranged in eye-catching terminal spikes, complemented by distinctive heart-shaped, serrated leaves.

Where Does It Call Home?

This endemic treasure is found exclusively in the Hawaiian Islands, specifically on O’ahu, Maui, and Hawai’i Island. In the wild, you’ll find it thriving in mesic to wet forests at elevations between 1,200 and 6,000 feet, where it enjoys the filtered light and consistent moisture of Hawaii’s mountain forests.

  • Species observed
  • No observations

A Critical Conservation Concern

Important Conservation Notice: Before we dive into growing tips, it’s crucial to understand that Hawai’i phyllostegia is critically endangered. With a Global Conservation Status of S1 (Critically Imperiled) and listed as Endangered in the United States, this species typically has five or fewer occurrences in the wild with very few remaining individuals.

If you’re interested in growing this plant, it’s absolutely essential to source it only from reputable native plant nurseries or conservation organizations that propagate from legally and ethically obtained material. Never collect from wild populations.

Why Grow Hawai’i Phyllostegia?

Despite its rarity challenges, there are compelling reasons to consider this plant for specialized gardens:

  • Conservation impact: Growing responsibly sourced plants helps preserve Hawaiian biodiversity
  • Pollinator support: The flowers attract native Hawaiian bees and other indigenous pollinators
  • Cultural significance: Part of Hawaii’s unique evolutionary story
  • Aesthetic value: Offers delicate beauty with its spikes of pale flowers and attractive foliage

Growing Conditions and Care

Hawai’i phyllostegia isn’t your typical backyard plant—it requires specific conditions that mimic its native forest habitat:

Climate Requirements

  • USDA Hardiness Zones 10-11 (or Hawaiian climate equivalents)
  • Prefers cooler, mountain-like conditions
  • Needs protection from strong winds

Light and Location

  • Partial shade to filtered light
  • Avoid full sun exposure
  • Benefits from morning sun with afternoon protection

Soil and Water

  • Well-draining soil that retains some moisture
  • Consistent moisture without waterlogging
  • Rich, organic soil similar to forest floor conditions

Best Garden Settings

This rare native is best suited for:

  • Native Hawaiian gardens
  • Conservation-focused landscapes
  • Specialized botanical collections
  • Educational gardens highlighting endangered species
  • Protected areas with controlled access

Planting and Care Tips

Successfully growing Hawai’i phyllostegia requires patience and attention to detail:

  • Site preparation: Choose a protected location that mimics forest understory conditions
  • Planting: Plant during cooler, wetter months when possible
  • Watering: Maintain consistent moisture but ensure excellent drainage
  • Mulching: Use organic mulch to retain moisture and suppress weeds
  • Monitoring: Watch carefully for signs of stress and adjust care accordingly

The Bottom Line

Hawai’i phyllostegia represents both an opportunity and a responsibility. While this endangered native offers unique beauty and ecological benefits, it should only be grown by dedicated gardeners committed to conservation and proper care. If you’re passionate about Hawaiian native plants and have the right growing conditions, consider reaching out to conservation organizations or specialized native plant nurseries to learn about responsible acquisition.

For most home gardeners, consider supporting conservation efforts through donations or volunteering, while exploring other Hawaiian native plants that are less critically endangered but equally beautiful for your native garden projects.

Phyllostegia floribunda is also known as...

Often we refer to plants by their common names. When shopping for plants the scientific name is the best way to positively identify the plant species you desire. But some plants have more than one name! While it doesn't happen often, nurseries might display one name while you're searching for another. Phyllostegia floribunda is also known as:

Phyllostegia floribunda var. forbesii | USDA symbol: PHFLF
Phyllostegia forbesii | USDA symbol: PHFO3
Phyllostegia villosa | USDA symbol: PHVI11

Why do some plants have more than one name? Over time plant species may be renamed for a few reasons:

  1. Botanists in different regions named the same plant without knowing it had already been classified.
  2. A species was reclassified after scientific advances in, for example, DNA analysis.
  3. Slight variations within a species are sometimes mistakenly identified as entirely new species.

Classification

Group: Dicot
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Subclass: Asteridae
Order: Lamiales
Family: Lamiaceae Martinov - Mint family
Genus: Phyllostegia Benth. - phyllostegia

Species: Phyllostegia floribunda Benth. - Hawai'i phyllostegia

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