North America Native Plant

White Kauai Rosemallow

Botanical name: Hibiscus waimeae hannerae

USDA symbol: HIWAH

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Synonyms: Hibiscus waimeae A. Heller var. hannerae O. Deg. & I. Deg. (HIWAH2)   

White Kauai Rosemallow: A Precious Hawaiian Treasure Worth Protecting Meet the white Kauai rosemallow (Hibiscus waimeae hannerae), one of Hawaii’s most endangered floral gems. This isn’t your typical backyard hibiscus – it’s a rare native shrub that’s fighting for survival on the Garden Isle of Kauai. If you’re dreaming of ...

Rare plant alert!

Region: United States

Status: S2T1: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is 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) ⚘ Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

White Kauai Rosemallow: A Precious Hawaiian Treasure Worth Protecting

Meet the white Kauai rosemallow (Hibiscus waimeae hannerae), one of Hawaii’s most endangered floral gems. This isn’t your typical backyard hibiscus – it’s a rare native shrub that’s fighting for survival on the Garden Isle of Kauai. If you’re dreaming of adding this beauty to your garden, hold that thought – there’s a lot more to this story than meets the eye.

What Makes This Hibiscus Special?

The white Kauai rosemallow is a perennial shrub that’s exclusively native to Hawaii, specifically the island of Kauai. As its common name suggests, this plant produces stunning white flowers that stand out against Hawaii’s lush green landscape. Like other hibiscus species, it’s a multi-stemmed woody plant that typically grows less than 13-16 feet tall, though environmental conditions can influence its final size.

You might also see this plant referenced by its botanical synonym, Hibiscus waimeae A. Heller var. hannerae O. Deg. & I. Deg., but don’t let the scientific names intimidate you – what matters most is understanding why this plant is so incredibly special.

Where Does It Grow?

This hibiscus calls only Hawaii home, and even more specifically, it’s found on Kauai. Talk about being picky about your zip code! This extremely limited geographical distribution is actually part of what makes the plant so vulnerable.

The Conservation Reality Check

Here’s where we need to have a serious conversation. The white Kauai rosemallow is listed as Endangered in the United States, with a Global Conservation Status of S2T1. This means every single plant matters for the species’ survival. We’re not just talking about a somewhat rare plant – we’re talking about a species that’s hanging on by a thread.

If you’re considering growing this plant, please understand that it should only be grown from responsibly sourced material, and ideally as part of legitimate conservation efforts. This isn’t a plant you’ll find at your local nursery, nor should it be casually collected from the wild.

Growing Conditions and Care

While specific growing information for this exact variety is limited due to its rarity, we can infer from its Hawaiian origins that it requires:

  • Tropical conditions (likely USDA zones 10-12 only)
  • Warm temperatures year-round
  • High humidity
  • Well-draining soil
  • Protection from strong winds

Given its endangered status, successful cultivation would require specialized knowledge and potentially permits or involvement with conservation organizations.

Role in the Garden and Landscape

In the rare instances where this plant might be grown, it would serve as:

  • A conservation specimen in botanical gardens
  • Part of specialized native Hawaiian plant collections
  • An educational tool for Hawaiian flora preservation
  • A symbol of Hawaii’s unique biodiversity

This isn’t a plant for typical landscaping – it’s a plant for preservation.

Pollinator and Wildlife Benefits

While specific data on wildlife benefits is limited, Hawaiian hibiscus species typically support native pollinators and may provide habitat for local wildlife. Every endangered plant plays a crucial role in its ecosystem, often in ways we’re still discovering.

What This Means for Gardeners

If you’re passionate about Hawaiian native plants, there are many other beautiful native hibiscus species that aren’t as critically endangered. Consider supporting conservation efforts for the white Kauai rosemallow while choosing more sustainable native alternatives for your garden.

The best way to help this species isn’t necessarily to grow it yourself, but to support the organizations working to protect its natural habitat and conduct legitimate propagation efforts. Sometimes the most loving thing we can do for a rare plant is to admire it from afar while working to ensure it has a future in the wild.

Remember: when it comes to endangered species, conservation comes first, cultivation comes second – and only when done responsibly.

White Kauai Rosemallow

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Malvales

Family

Malvaceae Juss. - Mallow family

Genus

Hibiscus L. - rosemallow

Species

Hibiscus waimeae A. Heller - white Kauai rosemallow

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