North America Native Plant

Western Moss Heather

Botanical name: Cassiope mertensiana var. gracilis

USDA symbol: CAMEG

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Western Moss Heather: A Tiny Alpine Treasure for Your Garden If you’ve ever hiked through the high country of the Pacific Northwest and marveled at those adorable little cushions of evergreen foliage dotted with tiny white bells, you’ve likely encountered western moss heather. This charming native shrub might be small ...

Western Moss Heather: A Tiny Alpine Treasure for Your Garden

If you’ve ever hiked through the high country of the Pacific Northwest and marveled at those adorable little cushions of evergreen foliage dotted with tiny white bells, you’ve likely encountered western moss heather. This charming native shrub might be small in stature, but it’s big on character and perfect for gardeners looking to bring a touch of alpine magic to their landscapes.

What Is Western Moss Heather?

Western moss heather (Cassiope mertensiana var. gracilis) is a delightful perennial shrub that’s as tough as it is beautiful. Despite its diminutive size, this little powerhouse is a true woody plant with multiple stems, though it rarely grows taller than a few inches to a foot high. Think of it as nature’s version of a living carpet – dense, evergreen, and absolutely charming.

Where Does It Call Home?

This native beauty is a true child of the American West, naturally occurring in Idaho, Montana, Oregon, and Washington. You’ll find it thriving in the high-elevation alpine and subalpine regions where the air is crisp and the views are spectacular.

Why You’ll Fall in Love with Western Moss Heather

There’s something irresistibly enchanting about western moss heather’s aesthetic appeal. Picture this: a dense mat of tiny, scale-like evergreen leaves that create a soft, moss-like texture (hence the name!). Come late spring to early summer, this green carpet becomes studded with delicate, nodding white bell-shaped flowers that look like they belong in a fairy garden.

The plant’s compact, cushion-like growth form makes it an absolute star in:

  • Rock gardens where it can spill over stones
  • Alpine garden collections
  • Native plant landscapes
  • Ground cover applications in challenging spots

The Perfect Garden Match

Western moss heather isn’t your typical suburban shrub – and that’s exactly what makes it special! This plant is tailor-made for gardeners who love a challenge and want something truly unique. It’s perfect for:

  • Alpine and rock gardens that mimic high-elevation conditions
  • Native plant gardens focused on Pacific Northwest species
  • Specialty collections for plant enthusiasts
  • Cool, mountainous properties with similar conditions to its native habitat

Growing Conditions: Keep It Cool and Well-Drained

Here’s where western moss heather gets a bit particular – but don’t let that scare you off! This alpine native thrives in USDA hardiness zones 3-6, so it’s definitely a cold-weather champion. Here’s what it needs to be happy:

  • Light: Full sun to partial shade (morning sun with afternoon protection in warmer areas)
  • Soil: Well-draining, acidic soil that mimics its mountain home
  • Moisture: Consistent moisture but never waterlogged – think mountain meadow, not swamp
  • Temperature: Cool conditions with good air circulation

Planting and Care Tips

Successfully growing western moss heather is like creating a little piece of alpine paradise in your garden. Here are the key tips for success:

  • Drainage is everything: Plant in raised beds, rock gardens, or slopes where water won’t pool
  • Soil preparation: Amend with organic matter and sand to create a loose, acidic growing medium
  • Mulching: Use small gravel or stone chips to mimic its natural habitat and improve drainage
  • Watering: Keep soil consistently moist but never soggy, especially during dry spells
  • Location: Choose a spot with good air circulation to prevent fungal issues

Wildlife and Pollinator Benefits

While western moss heather might be small, it pulls its weight in supporting local ecosystems. Its delicate flowers attract native bees and other small pollinators, making it a valuable addition to wildlife-friendly gardens. The dense, evergreen foliage can also provide shelter for small creatures and insects throughout the year.

Is Western Moss Heather Right for Your Garden?

Let’s be honest – western moss heather isn’t for every gardener or every garden. It’s a specialty plant that requires specific conditions and a bit of patience. However, if you’re looking for:

  • A unique native plant that’s truly special
  • Something perfect for rock or alpine gardens
  • A conversation starter that few neighbors will have
  • A plant that connects your garden to the wild mountain landscapes of the West

Then western moss heather might just be your new favorite plant! Just remember to respect its needs, provide excellent drainage, and give it the cool, well-ventilated conditions it craves. With a little care and the right location, you’ll have a tiny piece of alpine magic right in your own backyard.

Western Moss Heather

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

Ericales

Family

Ericaceae Juss. - Heath family

Genus

Cassiope D. Don - mountain heather

Species

Cassiope mertensiana (Bong.) G. Don - western moss heather

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