Native Plants

Molokai Phyllostegia

Phyllostegia hirsuta

USDA symbol: PHHI5

perennial vine

Hawaii: native

Meet the Molokai phyllostegia (Phyllostegia hirsuta), a remarkable shrub that’s become one of Hawaii’s most precious botanical treasures. This endemic Hawaiian native isn’t your typical garden center find – and for good reason. It’s critically imperiled and listed as endangered, making it one of the rarest plants you might ever ...

Molokai 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.

Molokai Phyllostegia: A Critically Endangered Hawaiian Native Worth Protecting

Meet the Molokai phyllostegia (Phyllostegia hirsuta), a remarkable shrub that’s become one of Hawaii’s most precious botanical treasures. This endemic Hawaiian native isn’t your typical garden center find – and for good reason. It’s critically imperiled and listed as endangered, making it one of the rarest plants you might ever encounter.

What Makes This Plant Special?

The Molokai phyllostegia is a perennial shrub belonging to the mint family, and like its minty relatives, it features distinctive square stems and opposite leaves. This multi-stemmed woody plant typically grows less than 13-16 feet tall, though it usually stays much smaller in its natural habitat. As a member of the Phyllostegia genus, it produces small, tubular flowers that add delicate beauty to Hawaii’s native forests.

Where Does It Call Home?

This plant is endemic to Hawaii, specifically to the island of Molokai, where it clings to existence in native forest understories. Its entire world consists of a few remaining populations on this single Hawaiian island, making it geographically one of the most restricted plants on Earth.

  • Species observed
  • No observations

The Reality Check: Why You Probably Shouldn’t (and Can’t) Grow It

Here’s where we need to have an honest conversation. The Molokai phyllostegia has a Global Conservation Status of S1, meaning it’s critically imperiled with typically five or fewer occurrences and very few remaining individuals (fewer than 1,000). It’s also officially listed as Endangered.

What does this mean for gardeners? Simply put, this isn’t a plant you can casually add to your landscape. In fact, you’re extremely unlikely to find it available anywhere, and that’s actually a good thing for the species’ survival.

If You Could Grow It (Hypothetically Speaking)

Should responsibly sourced material ever become available through conservation programs, here’s what this unique shrub would need:

  • Climate: USDA zones 10-11 (tropical Hawaiian conditions only)
  • Habitat: Forest understory conditions with filtered light
  • Soil: Well-draining soils that mimic native forest floors
  • Moisture: As a facultative upland plant, it usually prefers non-wetland conditions but can tolerate some moisture
  • Light: Partial shade, similar to its native forest habitat

The Bigger Picture: Conservation in Your Garden

While you can’t grow the Molokai phyllostegia, you can still make a difference. Consider these alternatives:

  • Support Hawaiian native plant conservation organizations
  • If you live in Hawaii, plant other native Phyllostegia species that are less endangered
  • Choose other native Hawaiian plants for your landscape
  • Spread awareness about Hawaii’s endangered plant species

Why This Plant Matters

The Molokai phyllostegia represents the incredible diversity and fragility of Hawaiian ecosystems. As an endemic species found nowhere else on Earth, it’s evolved unique characteristics over thousands of years. Its small tubular flowers likely support specialized native Hawaiian pollinators, making it an important piece of the ecological puzzle.

The Takeaway

Sometimes the most valuable plants are the ones we admire from afar. The Molokai phyllostegia serves as a reminder of what’s at stake when native habitats disappear. While you probably won’t be growing this rare beauty in your garden, knowing about it and supporting conservation efforts helps ensure that future generations might have a better chance of seeing it thrive.

If you’re passionate about native Hawaiian plants, focus on the many other wonderful species that can be responsibly cultivated. Your garden can still be a celebration of Hawaii’s natural heritage while leaving the rarest species to the conservation experts who are working tirelessly to save them.

Phyllostegia hirsuta 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 hirsuta is also known as:

Phyllostegia hirsuta var. laxior & | USDA symbol: PHHIL

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 hirsuta Benth. - Molokai phyllostegia

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