Introduction

Also known as Avena sempervirens, blue oat grass is an perennial, ornamental grass that has attractive thin gray-green, or blue leaves (Figure 1). Leaf blades grow to about 12 inches long and are ½ inch wide and taper to a fine point. Plants grow 18 to 30 inches tall. The glaucous foliage provides a welcomed contrast to a green border. Beige terminal panicles are produced in June through August, maturing to a light brown by the fall when they break apart and fall from the plant. Attractive, light brown fall foliage color persists throughout the winter.

General Information

Scientific name: Helictotrichon sempervirens

Pronunciation: hel-lick-toe-TRICK-awn sem-pur-VYE-renz

Common name(s): blue oat grass

Family: Gramineae

Plant type: perennial; herbaceous; ornamental grass

USDA hardiness zones: 5 through 8 (Figure 2)

Planting month for zone 7: year round

Planting month for zone 8: year round

Origin: not native to North America

Uses: edging; ground cover; border

Availablity: generally available in many areas within its hardiness range

Description

Height: .5 to 1 feet

Spread: 1 to 2 feet

Plant habit: round

Plant density: dense

Growth rate: slow

Texture: fine

Foliage

Leaf arrangement: most emerge from the soil, usually without a stem

Leaf type: simple

Leaf margin: entire

Leaf shape: linear

Leaf venation: parallel

Leaf type and persistence: deciduous

Leaf blade length: 12 to 18 inches

Leaf color: blue or blue-green

Fall color: brown or tan

Fall characteristic: showy

Flower

Flower color: brown

Flower characteristic: summer flowering

Fruit

Fruit shape: oval

Fruit length: less than .5 inch

Fruit cover: dry or hard

Fruit color: brown

Fruit characteristic: showy

Trunk and Branches

Trunk/bark/branches: not applicable

Current year stem/twig color: not applicable

Current year stem/twig thickness: not applicable

Culture

Light requirement: plant grows in full sun

Soil tolerances: acidic; slightly alkaline; sand; loam; clay

Drought tolerance: moderate

Soil salt tolerances: unknown

Plant spacing: 12 to 18 inches

Other

Roots: not applicable

Winter interest: no special winter interest

Outstanding plant: not particularly outstanding

Invasive potential: not known to be invasive

Pest resistance: no serious pests are normally seen on the plant

Use and Management

Blue oat grass is attractive as a single accent plant in a very small garden, or it can be massed in groups for a beautiful, fine-textured drift. Blue oat grass prefers a full sun exposure, but will tolerate light shade. It prefers a moist soil that is well drained, however it will tolerate sandy as well as heavy clay soils. No more than yearly fertilization is needed to keep plants healthy. Propagate by division.

They are often planted about 2 feet apart so they form a solid mass of fine-textured foliage. Blue oat grass looks nice in a rock garden planted by itself, or more commonly in groups in front of a shrub border or in a row along a walk. They should last for many years with little care.

Pests and Diseases

Blue oat grass may be prone to foliar diseases when grown in shade.