North America Native Plant

Hawai’i Silversword

Botanical name: Argyroxiphium sandwicense macrocephalum

USDA symbol: ARSAM

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Synonyms: Argyroxiphium macrocephalum A. Gray (ARMA16)   

The Magnificent Hawai’i Silversword: A Rare Jewel for Specialized Gardens Imagine a plant so stunning it looks like it belongs on another planet – that’s the Hawai’i silversword (Argyroxiphium sandwicense macrocephalum) for you! This extraordinary native Hawaiian plant is one of nature’s most spectacular creations, forming dramatic rosettes of silvery, ...

Rare plant alert!

Region: United States

Status: S2T2: Status is uncertain but is somewhere between the following rankings: 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) ⚘ Subspecies or variety is 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) ⚘ Threatened: Experiencing significant population decline or habitat loss that could lead to its endangerment if not addressed. ⚘

Region: United States

The Magnificent Hawai’i Silversword: A Rare Jewel for Specialized Gardens

Imagine a plant so stunning it looks like it belongs on another planet – that’s the Hawai’i silversword (Argyroxiphium sandwicense macrocephalum) for you! This extraordinary native Hawaiian plant is one of nature’s most spectacular creations, forming dramatic rosettes of silvery, sword-shaped leaves that shimmer in the sunlight like metallic sculptures.

What Makes the Hawai’i Silversword Special?

The Hawai’i silversword is a true Hawaiian endemic, meaning it exists nowhere else on Earth. This perennial shrub typically grows as a multi-stemmed woody plant, usually staying under 13-16 feet tall. What really sets it apart is its incredible flowering display – after years of growth, the plant sends up a magnificent tall stalk covered in hundreds of small flowers, creating a truly unforgettable spectacle.

Where Does It Naturally Grow?

This remarkable plant calls Hawaii home, specifically thriving in the high-elevation volcanic landscapes of the Hawaiian Islands. You’ll find it growing naturally in some of the most dramatic and challenging environments on Earth.

Important Conservation Alert

Before we dive into growing tips, here’s something crucial every gardener needs to know: the Hawai’i silversword is listed as Threatened with a Global Conservation Status of S2T2. This means it’s extremely rare and faces significant conservation challenges in the wild. If you’re considering adding this plant to your garden, please ensure you source it only from reputable, conservation-minded nurseries that propagate plants responsibly.

Why Gardeners Love (and Struggle With) Silverswords

Let’s be honest – the Hawai’i silversword is not your average garden plant! Here’s what makes it both irresistible and challenging:

The Appeal:

  • Absolutely stunning silvery foliage that creates dramatic focal points
  • Unique rosette growth form unlike anything else in your garden
  • Spectacular once-in-a-lifetime flowering display
  • Supports native Hawaiian pollinators when it blooms
  • Perfect conversation starter for any garden enthusiast

The Reality Check:

  • Extremely specific growing requirements that are nearly impossible to replicate outside Hawaii
  • Needs high elevation, volcanic soils, and very particular climate conditions
  • Very slow growth rate requiring years of patience
  • Limited to USDA zones 10-11 with high elevation considerations

Growing Conditions and Care

If you’re determined to try growing a Hawai’i silversword (and live in an appropriate climate), here’s what you need to know:

  • Soil: Well-draining, volcanic or sandy soils with excellent drainage
  • Climate: High elevation tropical conditions with cool temperatures and low humidity
  • Water: Minimal watering – these plants are adapted to harsh, dry conditions
  • Location: Full sun with protection from extreme weather
  • Patience: Extremely slow growing – expect to wait many years for significant development

Best Garden Settings

The Hawai’i silversword works best in:

  • Specialized rock gardens with volcanic elements
  • Native Hawaiian plant collections
  • Xerophytic gardens designed for drought-tolerant plants
  • Educational or botanical garden settings

The Bottom Line

The Hawai’i silversword is undeniably one of the most spectacular plants on Earth, but it’s definitely not for every gardener or every garden. Its specific growing requirements make it extremely challenging to cultivate outside its native Hawaiian habitat. However, for those lucky enough to live in appropriate conditions and committed to supporting conservation efforts, growing this rare beauty can be an incredibly rewarding experience.

Remember, by choosing to grow threatened native species like the Hawai’i silversword with responsibly sourced plants, you’re not just adding beauty to your garden – you’re also supporting important conservation efforts. Just make sure you’re up for the challenge and have the right conditions to give this magnificent plant the specialized care it deserves!

Hawai’i Silversword

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

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Argyroxiphium DC. - silversword

Species

Argyroxiphium sandwicense DC. - Hawai'i silversword

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