North America Non-native Plant

Silver Hairgrass

Botanical name: Aira caryophyllea var. cupaniana

USDA symbol: AICAC3

Life cycle: annual

Habit: grass

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Synonyms: Aira cupaniana Guss. (AICU)   

Silver Hairgrass: A Delicate Mediterranean Grass in California Gardens If you’ve ever stumbled across tiny, wispy grass tufts in disturbed areas around California, you might have encountered silver hairgrass (Aira caryophyllea var. cupaniana). This diminutive annual grass brings a delicate texture to the landscape, though it’s probably not what most ...

Silver Hairgrass: A Delicate Mediterranean Grass in California Gardens

If you’ve ever stumbled across tiny, wispy grass tufts in disturbed areas around California, you might have encountered silver hairgrass (Aira caryophyllea var. cupaniana). This diminutive annual grass brings a delicate texture to the landscape, though it’s probably not what most gardeners have in mind when planning their dream garden.

What Is Silver Hairgrass?

Silver hairgrass is a small annual grass that belongs to the same family as many of our beloved lawn grasses. Also known by its synonym Aira cupaniana, this variety represents a Mediterranean form of the species that has made itself at home in California. As an annual, it completes its entire life cycle within one growing season, sprouting, growing, flowering, setting seed, and dying all within the same year.

This grass falls into the broader category of graminoids – that’s the fancy term for grass and grass-like plants, including true grasses, sedges, and rushes. But don’t expect this one to carpet your yard like traditional turf grass!

Where You’ll Find It

Silver hairgrass has established itself in California, where it grows as a non-native species that reproduces on its own without human intervention. Originally from Mediterranean regions, it has adapted to California’s similar climate conditions.

Should You Plant Silver Hairgrass in Your Garden?

Here’s where things get interesting – and a bit complicated. While silver hairgrass isn’t necessarily harmful, it’s also not particularly exciting from a gardening perspective. This tiny grass offers limited ornamental value due to its small stature and brief growing season. As an annual, it appears, does its thing, and disappears, leaving gaps in your garden design.

Since this is a non-native species, many gardeners prefer to focus on native alternatives that provide similar aesthetic benefits while supporting local ecosystems.

Native Alternatives to Consider

Instead of silver hairgrass, consider these beautiful native California grasses that offer more reliable garden performance and ecological benefits:

  • California fescue (Festuca californica) – A perennial bunchgrass with blue-green foliage
  • Purple needlegrass (Stipa pulchra) – California’s state grass with elegant, flowing seed heads
  • Deergrass (Muhlenbergia rigens) – A striking ornamental bunch grass
  • Blue wildrye (Elymus glaucus) – Attractive blue-tinted foliage

Growing Conditions and Care

If you do encounter silver hairgrass growing naturally on your property, it typically thrives in:

  • Dry, sandy soils
  • Disturbed areas and open spaces
  • Areas with minimal competition from other plants
  • Mediterranean-type climates with dry summers

As an annual, it requires no ongoing care – it simply grows, reproduces, and dies back naturally. However, this also means it won’t provide consistent year-round structure in your garden design.

The Bottom Line

While silver hairgrass isn’t invasive or harmful, it’s also not particularly useful for most gardening goals. Its small size, annual nature, and non-native status make it a less-than-ideal choice for intentional landscaping. Instead, consider the many beautiful native California grasses that offer superior garden performance, year-round interest, and valuable habitat for local wildlife.

If you’re drawn to the delicate, fine-textured look that silver hairgrass provides, explore native alternatives that can give you that same aesthetic appeal while supporting your local ecosystem. Your garden – and California’s native wildlife – will thank you for it!

Silver Hairgrass

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

Aira L. - hairgrass

Species

Aira caryophyllea L. - silver hairgrass

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