Helictotrichon spp.

oat grass

Poaceae

Europe, the Mediterranean, and temperate Asia

Drought Tolerant Container Friendly

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 4–9

Overview

Helictotrichon spp. is a genus of roughly 90 cool-season, tuft-forming grasses in the family Poaceae, native to Europe, the Mediterranean, and temperate Asia. Plants form dense, rounded clumps of narrow leaves and send up slender flowering stems that carry open, oat-like panicles. A frequently grown species, H. sempervirens, makes a fountain of stiff, blue-grey blades about 18-24 inches (45-60 cm) high, with flower stems reaching 3-4 feet (90-120 cm); the genus as a whole spans 1-5 feet (30-150 cm) in flower. Leaf color ranges from steely blue to plain green, and the foliage stays through mild winters, tattering in cold ones. The panicles open with a faint bluish or purple cast and ripen to straw. Clumps are long-lived but can die out in the center on heavy or wet soil. The blades can cut the skin if pulled, so dead foliage is combed out rather than gripped hard.

Native Range

Native to temperate and Mediterranean Europe, North Africa, and across temperate Asia, on dry grassland, open slopes, and rocky ground. Several species grow in mountain habitats with cold winters and bright summers.

Suggested Uses

Used in gravel gardens, dry borders, and mass plantings, spaced 18-24 inches (45-60 cm) apart for a continuous drift. The blue-grey clumps contrast with broad-leaved perennials and dark gravel. Cut panicles are used fresh or dried.

How to Identify

Recognized as a tight, rounded tussock of narrow leaves, often blue-grey, topped by airy one-sided panicles of oat-like spikelets on wiry stems. Each spikelet has a bent, twisting awn that catches the light. The clump keeps its shape year-round rather than dying back fully to the ground.

Appearance

Size & Dimensions

Height1' - 5'

Width/Spread1' - 2'

Colors

Flower Colors

tan

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~4 weeks

Summer

Flowering stems rise in early summer, generally June to July, lifting the panicles well above the foliage. The spikelets shift from a bluish tint to straw as seed ripens. Faded stems hold into autumn unless cut away.

Detailed Descriptions

Flower Description

bluish aging to straw

Foliage Description

blue-grey to green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.8(Neutral)

357912

Soil Types

loam sand rocky chalk

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

2-3 years to full clump

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

These grasses grow in full sun and sharply drained soil of low to moderate fertility. They are adapted to dry conditions and are damaged by heavy, wet ground, where clumps rot or thin out at the center. Most species are cold hardy to USDA zone 4 and tolerate heat once established. Lean soil and good air movement keep foliage firm and well colored. Watering is needed only during extended drought on established clumps. Division in spring renews tired centers and increases stock.

Pruning

Evergreen and semi-evergreen clumps are combed through in late winter to pull out dead blades rather than cut to the ground. Where foliage is badly tattered, clumps can be sheared low before spring growth. Spent flower stems are removed at any time.