Eriocoma spp.

Native to North America

HardinessZones 4–9

Overview

Eriocoma spp. is a genus of perennial bunchgrasses in the family Poaceae, native mainly to western North America, with species segregated from the older genera Achnatherum spp., Stipa spp., and Oryzopsis spp.. The most familiar member is E. hymenoides, Indian ricegrass, a cool-season grass of arid plains and deserts. Plants form dense tufts of slender, rolled leaves and send up airy flowering panicles reaching about 12 to 30 in (30 to 75 cm) tall. The open panicles carry seeds on slender, spreading branches that give the seed head an airy, cloud-like look as it ripens to straw. Eriocoma spp. species are adapted to dry, sandy, and alkaline soils and are valued in their range as drought-tolerant forage and for revegetating disturbed dryland. The large seeds of Indian ricegrass were a traditional food of Indigenous peoples of the Great Basin and Southwest. As cool-season grasses, they grow and flower in spring and early summer, then go dormant and pale through the heat of late summer. Heavy, wet soils are poorly tolerated and shorten the life of the clumps.

Native Range

Native to western North America, from the dry interior of Canada through the Great Basin, Rocky Mountains, and Southwest into northern Mexico. Eriocoma spp. grows on sandy plains, deserts, and dry slopes, often in alkaline soils.

Suggested Uses

Eriocoma spp. species are grown in native, prairie, and dry gardens, and used widely for forage and for revegetating arid, disturbed land. The airy seed heads add movement and texture in naturalistic plantings. Seed feeds birds and small mammals, and the clumps give cover in open dryland.

How to Identify

Dense tufts of slender, rolled leaves and tall, open flowering panicles mark Eriocoma spp.. In Indian ricegrass the panicle branches spread widely and fork, each tipped with a single plump seed in a short hairy husk. The airy, much-branched seed head over a tight bunch of narrow leaves is the clearest feature.

Appearance

Size & Dimensions

Height1' - 2'6"

Width/Spread8" - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Spring Summer

Flowering occurs in spring and early summer, roughly April to June, as cool-season growth peaks. The open panicles rise above the foliage and ripen seed over several weeks. Plants then go dormant and pale during summer heat, greening again with autumn and winter moisture.

Detailed Descriptions

Flower Description

Greenish to straw

Foliage Description

Green to grey-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 Range6.5 - 8.5(Alkaline)

357912

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Eriocoma spp. species grow in full sun on dry, sandy, or gravelly soils, including alkaline ground to about pH 8.5. They are cool-season bunchgrasses, making most growth in spring and autumn and resting through summer heat. Very little water is needed once established, and the plants are adapted to long drought. Sharp drainage is important, as heavy or wet soils rot the crowns and shorten plant life. Establishment from seed can be slow and uneven, since the seed has a dormancy that needs cold or weathering to break. Once settled, the clumps are long-lived in suitable dryland conditions.

Pruning

Old growth can be cut back in late winter before new spring growth begins. Dormant straw-coloured foliage is otherwise left over summer and winter. Clumps are not divided often, as they re-establish slowly after disturbance.