Deergrass (Muhlenbergia rigens) - purple flowers, illustrated plant cardIllustration

Deergrass

Muhlenbergia rigens

Deergrass blooms from September through November.

Bloom calendar
Bloom time
Sep–Nov
checked
Hardiness
Zones 6–11
checked
Sun
Full sun
checked
Water
Low water
checked
Mature size
5 ft × 4 ft
checked
Type
Grass
house classification

Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.

Growing Deergrass

Plant it in full sun. It prefers low water. It is hardy in USDA zones 6–11. Expect it to reach about 5 ft tall and 4 ft wide at maturity, in roughly 3 years (a house reading).

Pets

  • Not yet checked for pets.

Lists differ and none is complete. If a pet eats a plant and seems unwell, call a veterinarian or a pet poison helpline.

No toxicity note is on file for Deergrass. That is not a clearance: check its safety for people and pets before planting.

Verification
What was checked

Nine facts were checked against named botanical sources, each recorded beside the sources that carried it: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Soil, diseases, pests, toxicity and the plant's own names have not yet been read for this plant, and its trait tags are the ones a feature uses rather than every word a page prints. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.

See the 7 sources it was checked against

When to plant Deergrass

Plant Deergrass in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 8, the middle of its hardy zones 6 to 11, spring means February to April and fall means September or October. Once settled, it blooms from September to November.

Month-by-month timing for your zone is on the planting calendar; if you garden near zone 8, the middle of this plant's hardy range, start with zone 8 in February. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.

How big does Deergrass get?

Illustration of Deergrass drawn to scale beside an adult5 fttall5 ft 7 inan adult4 ftwide
About 5 ft tall and 4 ft wide at maturity: about as tall as an adult.

See Deergrass in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.

How far apart to plant Deergrass

Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.

Space Deergrass about 4 ft apart, center to center, so each plant has room to reach its full width.

Plant them
4 ft apart
Per 10 sq ft
one needs about 16 sq ft
4 by 8 ft bed
about 2

Add Deergrass to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.

Where these facts come from

Deergrass' height, spread, hardiness zones, sun, water, bloom months and color and trait tags were checked against 7 published sources on October 21, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.

  • Missouri Botanical Gardenheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
  • tynursery.comT-Y Nurseryheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
  • devilmountainnursery.comDevil Mountain Wholesale Nurseryheight, spread, hardiness zones, water, bloom months and color and trait tags
  • waterwisegardenplanner.orgChino Basin Water Conservation District, Waterwise Garden Plannerheight, spread, sun, water, bloom months and color and trait tags
  • apps.cals.arizona.eduUniversity of Arizona Campus Arboretumheight, spread, sun, water and bloom months and color
  • laspilitas.comLas Pilitas Nurseryheight, spread, hardiness zones, water and trait tags
  • yavapaiplants.extension.arizona.eduUniversity of Arizona Cooperative Extension, Yavapai Countyheight and bloom months and color

How the checking works, and what each standard covers, is on the verified plants page.

Where it grows wild

Native to 5 states

United States: Arizona, California, Nevada, New Mexico, Texas

Recorded growing wild in 54 counties.

Range data from the World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 4.0, adapted) and USDA PLANTS. How the native range is credited.

The Muhly Grass group

One of 4 in the Muhly Grass group. Same genus, similar care.

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Design a garden with this

Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.

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