Grasses

Helictotrichon sempervirens

Blue oat grass

Helictotrichon sempervirens; web-sized from original image.

Arching, steel-blue leaves form a bristly mound with airy flower stems rising above it in summer. This cool-season grass provides a strong blue accent in sunny borders and gravel gardens. Good airflow and drainage are essential: hot, humid conditions and soggy winter soil can spoil the foliage or rot the crown.

At a glance

Sun: Full sun
Mature size: 2–3 ft. tall × 1–2½ ft. wide
Water: Dry to average
Hardiness: USDA 4–8
Bloom: Summer; flowers age to gold.

Sizes & prices

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Catalog updated September 8, 2026. This is not a live stock count; please call to confirm availability and price.

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Resistance & tolerances

Deer: Generally resistant; not browse-proof.
Drought: Tolerant once established.
Wet soil: Poor tolerance; winter wet can cause crown rot.

Resistance is not a guarantee; deer and rabbits may browse any plant.

Seasonal interest

Habit: Clumping; semi-evergreen in colder climates.

Growing & care

Soil: Well-drained soil; neutral to alkaline preferred.
Pruning: Remove dead leaves and spent flower stems in spring.
Division: Divide in spring as needed.

Sources & photo credits

NC State Extension

Photo: Drew Avery · CC BY 2.0

Reviewed October 1, 2026. Growing conditions vary by location.