North America Native Plant

Slimstem Reedgrass

Botanical name: Calamagrostis stricta stricta

USDA symbol: CASTS5

Life cycle: perennial

Habit: grass

Native status: Native to Alaska âš˜ Native to Canada âš˜ Native to Greenland âš˜ Native to the lower 48 states  

Slimstem Reedgrass: A Hardy Native Grass for Challenging Landscapes If you’re looking for a tough-as-nails native grass that can handle whatever Mother Nature throws at it, meet slimstem reedgrass (Calamagrostis stricta stricta). This unassuming perennial grass might not win any beauty contests, but it’s the kind of reliable workhorse that ...

Slimstem Reedgrass: A Hardy Native Grass for Challenging Landscapes

If you’re looking for a tough-as-nails native grass that can handle whatever Mother Nature throws at it, meet slimstem reedgrass (Calamagrostis stricta stricta). This unassuming perennial grass might not win any beauty contests, but it’s the kind of reliable workhorse that every native garden needs.

What Makes Slimstem Reedgrass Special?

Slimstem reedgrass is a true North American native, naturally occurring across an impressive range from Alaska and Greenland all the way down through the Canadian provinces and into many U.S. states. You’ll find this hardy grass thriving in places like Alberta, British Columbia, Alaska, and extending south through states including California, Colorado, Idaho, Maine, Michigan, Minnesota, Montana, and many others.

This widespread distribution tells you something important: this grass is incredibly adaptable and resilient. It’s the kind of plant that has been quietly doing its job in nature’s landscapes for thousands of years.

Garden Appeal and Landscape Role

Let’s be honest – slimstem reedgrass isn’t going to stop traffic with flashy blooms. Its yellow flowers are subtle rather than showy, and it grows in a classic upright, clumping form reaching about 3 feet tall. The green foliage has a medium texture that provides a nice backdrop for more colorful native wildflowers.

But here’s where this grass really shines: it’s perfect for those challenging spots in your landscape where other plants struggle. Think naturalized areas, rain gardens, or anywhere you need reliable ground cover that can handle moisture fluctuations.

Growing Conditions and Care

Slimstem reedgrass is refreshingly straightforward to grow, especially if you match its preferred conditions:

  • Soil: Prefers fine to medium-textured soils (avoid very sandy conditions)
  • Moisture: Likes consistent moisture – this isn’t a drought-tolerant grass
  • pH: Adaptable to slightly acidic to neutral soils (5.5 to 7.5)
  • Light: Can handle partial shade to full sun
  • Climate: Extremely cold hardy (survives temperatures down to -43°F!)

The grass has a moderate growth rate and spreads through underground stems (rhizomes), so it will gradually fill in an area without being aggressive about it. It’s active during spring and summer, then provides some nice fall interest before going dormant in winter.

Planting and Maintenance Tips

Getting slimstem reedgrass established requires a bit of patience. The seeds have low vigor as seedlings, so don’t expect instant gratification. Here are some tips for success:

  • Start with seed (it’s rarely available as container plants)
  • Plant in spring for best establishment
  • Keep soil consistently moist during the first growing season
  • Be patient – this grass takes time to establish but is long-lived once settled
  • Minimal fertilizer needed (medium fertility requirements)

Wildlife and Ecological Benefits

While slimstem reedgrass may not be a pollinator magnet (it’s wind-pollinated like most grasses), it serves important ecological functions. Native grasses like this provide habitat structure, help prevent erosion, and support the broader ecosystem that native wildlife depends on.

Is Slimstem Reedgrass Right for Your Garden?

This grass is ideal if you:

  • Want to support native plant communities
  • Have consistently moist areas that need coverage
  • Live in a cold climate where many other grasses struggle
  • Appreciate subtle, naturalistic beauty over flashy displays
  • Need a low-maintenance ground cover for large areas

Skip this one if you’re looking for drought tolerance, instant results, or dramatic visual impact. Slimstem reedgrass is more about quiet reliability than garden glamour.

In the world of native gardening, sometimes the most valuable plants are the ones that simply show up and do their job year after year. Slimstem reedgrass is exactly that kind of dependable garden citizen – and our native landscapes are better for having it around.

How

Slimstem Reedgrass

Grows

Growing season

Spring and Summer

Lifespan

Long

Growth form & shape

Rhizomatous and Erect

Growth rate

Moderate

Height at 20 years
Maximum height

3.0

Foliage color

Green

Summer foliage density

Dense

Winter foliage density

Porous

Foliage retention

No

Flowering

No

Flower color

Yellow

Fruit/seeds

No

Fruit/seed color

Brown

Allelopath

No

Nitrogen fixing

None

Toxic

None

C:N Ratio

Medium

Fire Resistant

No

Foliage Texture

Medium

Low-growing Grass

Yes

Resproutability

No

Coppice Ability

No

Bloat

None

Slimstem Reedgrass

Growing Conditions

Adapted to Coarse Soil

No

Adapted to Medium Soil

Yes

Adapted to Fine Soil

Yes

Anaerobic tolerance

Medium

CaCO₃ tolerance

Low

Cold Stratification

No

Drought tolerance

Low

Nutrient requirement

Medium

Fire tolerance

Medium

Frost-free days minimum

90

Hedge tolerance

None

Moisture requirement

High

pH range

5.5 to 7.5

Plants per acre

11000 to 18000

Precipitation range (in)

24 to 60

Min root depth (in)

7

Salt tolerance

None

Shade tolerance

Intermediate

Min temperature (F)

-43

Cultivating

Slimstem Reedgrass

Flowering season

Late Spring

Commercial availability

Contracting Only

Fruit/seed abundance

Low

Fruit/seed season

Spring to Summer

Fruit/seed persistence

No

Propagated by bare root

No

Propagated by bulb

No

Propagated by container

No

Propagated by corm

No

Propagated by cuttings

No

Propagated by seed

Yes

Propagated by sod

No

Propagated by sprigs

Yes

Propagated by tubers

No

Seed per pound

1400000

Seed spread rate

Slow

Seedling vigor

Low

Small grain

No

Vegetative spread rate

Moderate

Slimstem Reedgrass

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

Calamagrostis Adans. - reedgrass

Species

Calamagrostis stricta (Timm) Koeler - slimstem reedgrass

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