North America Native Plant

Stillman’s Needlegrass

Botanical name: Achnatherum stillmanii

USDA symbol: ACST7

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Synonyms: Stipa stillmanii Bol. (STST2)   

Stillman’s Needlegrass: A Rare California Native Worth Protecting in Your Garden Meet Stillman’s needlegrass (Achnatherum stillmanii), a delicate and graceful native California grass that’s as beautiful as it is important to our local ecosystems. This perennial grass might not be the showiest plant in the garden center, but for those ...

Rare plant alert!

Region: Conservation status by state

Status: S3: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Stillman’s Needlegrass: A Rare California Native Worth Protecting in Your Garden

Meet Stillman’s needlegrass (Achnatherum stillmanii), a delicate and graceful native California grass that’s as beautiful as it is important to our local ecosystems. This perennial grass might not be the showiest plant in the garden center, but for those who appreciate subtle beauty and want to support native biodiversity, it’s a real gem.

What Makes Stillman’s Needlegrass Special?

Stillman’s needlegrass is a true California native, found naturally only in the Golden State. You might also see it listed under its former scientific name, Stipa stillmanii, but today botanists recognize it as Achnatherum stillmanii. This fine-textured perennial grass produces delicate, feathery seed heads that catch the light beautifully and add movement to the garden with every breeze.

Where Does It Grow?

This grass is endemic to California, calling the Sierra Nevada and adjacent mountain ranges home. It’s perfectly adapted to the state’s Mediterranean climate and diverse terrain, making it an excellent choice for gardeners looking to create authentic California landscapes.

An Important Conservation Note

Here’s something every responsible gardener should know: Stillman’s needlegrass has a Global Conservation Status of S3, meaning it’s considered vulnerable in the wild. With typically only 21 to 100 occurrences and between 3,000 and 10,000 individuals remaining, this grass is rare and precious. If you choose to grow it, please make sure you’re obtaining plants or seeds from reputable native plant nurseries that source their material responsibly – never collect from wild populations.

Why Grow Stillman’s Needlegrass?

Despite its rarity in nature, this grass can be a wonderful addition to the right garden:

  • Authentic native landscaping: Perfect for creating genuine California ecosystems in your yard
  • Low maintenance: Once established, it’s drought-tolerant and requires minimal care
  • Subtle beauty: Provides fine texture and gentle movement with delicate, feathery seed heads
  • Wildlife habitat: Offers structure and shelter for beneficial insects and small wildlife
  • Conservation impact: Growing it responsibly helps preserve genetic diversity of this vulnerable species

Growing Conditions and Care

Stillman’s needlegrass thrives in USDA hardiness zones 7-10, making it suitable for most of California and similar Mediterranean climates. Like many California natives, it prefers:

  • Sun exposure: Full sun to partial shade
  • Soil: Well-draining soils (it won’t tolerate soggy conditions)
  • Water: Drought-tolerant once established, though some summer water helps
  • Maintenance: Minimal – just occasional removal of old growth

Planting and Establishment Tips

The best time to plant Stillman’s needlegrass is in fall, which allows the roots to establish during the cooler, wetter months. Here’s how to give it the best start:

  • Plant in well-amended, fast-draining soil
  • Water regularly the first year while roots establish
  • After establishment, reduce watering significantly
  • Allow seed heads to develop for natural reseeding (where appropriate)
  • Cut back old growth in late winter if desired

Garden Design Ideas

This grass works beautifully in several landscape styles:

  • Native plant gardens: Combine with other California natives like ceanothus and penstemon
  • Naturalistic landscapes: Use in meadow-style plantings for authentic wildland appeal
  • Xeriscapes: Excellent for drought-tolerant garden designs
  • Slope stabilization: Its root system helps prevent erosion on gentle slopes

The Bottom Line

Stillman’s needlegrass isn’t for every garden or every gardener, but for those passionate about native plants and conservation, it offers a unique opportunity to grow something truly special. Its vulnerable status means we should approach it with respect and responsibility, but that same rarity makes it all the more valuable in our gardens.

If you’re creating a native California landscape and can source this grass responsibly, you’ll be rewarded with a beautiful, low-maintenance plant that connects your garden to the state’s natural heritage. Just remember: with great plants comes great responsibility – always choose nursery-grown plants from reputable sources, never wild-collected specimens.

Stillman’s Needlegrass

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Poaceae Barnhart - Grass family

Genus

Achnatherum P. Beauv. - needlegrass

Species

Achnatherum stillmanii (Bol.) Barkworth - Stillman's needlegrass

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