North America Native Plant

Waianae Range Yellow Loosestrife

Botanical name: Lysimachia waianaeensis

USDA symbol: LYWA3

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Waianae Range Yellow Loosestrife: A Rare Hawaiian Mountain Treasure If you’re passionate about Hawaiian native plants and conservation gardening, you may have heard whispers about the elusive Waianae Range yellow loosestrife (Lysimachia waianaeensis). This remarkable shrub is one of Hawaii’s botanical gems, but before you start planning where to plant ...

Rare plant alert!

Region: Conservation status by state

Status: S1S2Q: Status is uncertain but is somewhere between the following rankings: Uncertain taxonomy: ⚘ 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) ⚘

Waianae Range Yellow Loosestrife: A Rare Hawaiian Mountain Treasure

If you’re passionate about Hawaiian native plants and conservation gardening, you may have heard whispers about the elusive Waianae Range yellow loosestrife (Lysimachia waianaeensis). This remarkable shrub is one of Hawaii’s botanical gems, but before you start planning where to plant it, there’s something crucial you need to know about its conservation status.

What Makes This Plant Special?

The Waianae Range yellow loosestrife is a perennial shrub that’s as rare as it is beautiful. This multi-stemmed woody plant typically grows to heights of 13-16 feet, though it can vary depending on environmental conditions. What makes it truly special isn’t just its cheerful yellow flowers, but its incredible rarity and the fact that it’s found nowhere else on Earth except in Hawaii’s mountains.

Where Does It Come From?

This endemic Hawaiian species calls the Waianae Mountains of Oahu home, making it a true island original. As a plant that’s native exclusively to Hawaii, it represents millions of years of isolated evolution that created something completely unique to these Pacific islands.

The Rarity Reality Check

Here’s where we need to have a serious conversation. The Waianae Range yellow loosestrife has a Global Conservation Status of S1S2Q, which signals that this plant is extremely rare and potentially at risk. This isn’t your typical garden center find – we’re talking about a species that needs our protection more than our cultivation.

Important: If you’re considering growing this plant, you must only source it through responsible channels that support conservation efforts. Never collect from wild populations, and always verify that any plants you acquire are ethically propagated.

Garden Role and Landscape Design

In the right hands and the right garden, this shrub can serve as:

  • A centerpiece in native Hawaiian plant collections
  • An educational specimen in botanical or conservation gardens
  • Part of habitat restoration projects (with proper permits and guidance)
  • A conversation starter about Hawaiian plant conservation

Growing Conditions and Care

Given its mountain origins, the Waianae Range yellow loosestrife likely prefers:

  • Cool, moist conditions similar to Hawaiian mountain forests
  • Well-draining soil with good organic content
  • Protection from harsh winds and extreme heat
  • USDA zones 10-12 (tropical conditions)

However, specific growing requirements aren’t well-documented due to the plant’s rarity, so success would require careful observation and possibly consultation with Hawaiian native plant experts.

Should You Grow It?

The short answer is: only if you’re deeply committed to conservation and can source it responsibly. This isn’t a plant for casual gardeners or those looking for easy-care landscaping options. It’s a species that deserves respect, careful stewardship, and a commitment to its preservation.

If you’re interested in supporting Hawaiian native plants but want more readily available options, consider researching other native Hawaiian species that are less critically rare but equally beautiful and important for local ecosystems.

The Bottom Line

The Waianae Range yellow loosestrife represents both the incredible botanical diversity of Hawaii and the fragility of island ecosystems. While it may be tempting to want this rare beauty in your garden, the most important thing we can do for this species is protect its wild populations and support legitimate conservation efforts.

If you do decide to pursue growing this plant, make sure you’re working with reputable native plant societies, botanical gardens, or conservation organizations that can guide you toward ethical sourcing and proper care techniques.

Waianae Range Yellow Loosestrife

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

Primulales

Family

Primulaceae Batsch - Primrose family

Genus

Lysimachia L. - yellow loosestrife

Species

Lysimachia waianaeensis H. St. John - Waianae Range yellow loosestrife

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