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Dieteria spp.

tansyasters

Asteraceae Western North America

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Container Friendly

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 4–9

Overview

Dieteria spp. is a genus of three species of annual, biennial, and short-lived perennial herbs in the family Asteraceae, native to dry regions of western North America. Known as tansyasters, plants grow 6 in to 4 ft (15-120 cm) tall, with branched, often gray-hairy stems and narrow, toothed or lobed leaves. The aster-like flower heads are 0.8-1.5 in (2-4 cm) across, with many slender ray florets in violet, lavender, or purple-blue surrounding a yellow disc. D. canescens, hoary tansyaster, occurs across plains, sagebrush, and open woodland from Canada to Mexico. Plants bloom from summer into autumn and often grow as colonizers of disturbed, gravelly ground. They tolerate heat, drought, and alkaline soils, and the deep roots help them persist in arid sites. Most plants behave as annuals or biennials, completing their cycle in one or two seasons before setting abundant seed.

Native Range

Dieteria spp. is native to western North America, from western Canada south through the western United States to northern Mexico. Plants grow in dry plains, foothills, sagebrush steppe, and open montane woodland. The genus was formerly included in Machaeranthera spp..

Suggested Uses

Grown in native and pollinator gardens, dryland plantings, and wildflower seed mixes across the western United States. The late-season flowers draw bees and butterflies when many plants have finished. Tolerant of poor, alkaline soil, the plants fill low-water beds and restoration plantings.

How to Identify

Look for branched, gray-hairy stems bearing narrow, toothed leaves and aster-like heads with many thin violet to purple ray florets around a yellow disc. The phyllaries are narrow, green-tipped, and spreading or curved back. Tansyasters resemble true asters but carry bristly, glandular foliage and grow in dry, open western habitats.

Appearance

Size & Dimensions

Height6" - 4'

Width/Spread8" - 2'

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~10 weeks

Summer Fall

Flowering runs from midsummer into autumn, generally July to October, peaking after summer rains. The heads open over many weeks and draw native bees and butterflies. Plants set abundant wind-dispersed seed as the season ends.

Detailed Descriptions

Flower Description

violet to purple-blue with yellow center

Foliage Description

gray-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 - 8.0(Alkaline)

357912

Soil Types

sand rocky loam

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plants grow in full sun and well-drained, gritty or sandy soil with a pH near 6.5 to 8.0, including alkaline ground. They tolerate heat and drought once established and decline in rich, moist, or poorly drained soils. Seed is sown in autumn or spring, and plants often self-sow in open, disturbed sites. Watering is minimal once seedlings root. Annual and biennial plants die after flowering and renew from seed.

Pruning

Spent flower heads are removed to extend bloom or left to ripen for seed and to feed birds. Tall plants are cut back lightly in early summer to limit flopping. Annual and biennial plants are cleared once they finish their cycle.