Machaeranthera tanacetifolia (Tahoka daisy)

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Machaeranthera spp.

tansyaster

Asteraceae Western and central North America

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 4–9

Overview

Machaeranthera spp. is a genus of annual, biennial, and perennial herbs in the daisy family (Asteraceae), native to western and central North America, where many species grow on dry plains, deserts, and rocky slopes. Recent botanical work has moved many former members to related genera such as Dieteria spp. and Xanthisma spp., leaving a smaller core group. Plants grow 6 to 24 inches (15 to 60 cm) tall, with branched, leafy stems and toothed or deeply cut leaves that are sometimes spine-tipped. The daisy-like flower heads have violet, blue-purple, or lavender ray florets surrounding a yellow disk, 1 to 2 inches (2.5 to 5 cm) across. M. tanacetifolia, the tahoka daisy, is an annual grown from seed for its purple flowers and finely divided foliage. Bloom comes mainly in summer and autumn, often after rain. Plants grow in full sun on lean, well-drained soils and withstand heat and drought. The open flowers draw bees and butterflies. Many species are short-lived, persisting through self-sown seed.

Native Range

Native to western and central North America, from the Great Plains across the Rocky Mountains and Great Basin to the deserts of the Southwest and northern Mexico, growing in grassland, sagebrush, and pinyon-juniper country.

Suggested Uses

Grown in wildflower meadows, native plant and rock gardens, and xeriscapes, where the purple daisies combine with grasses and other dry-land plants. The tahoka daisy is used as a fast annual for sunny, sandy beds and naturalized drifts. The flowers are a nectar source for native bees and butterflies.

How to Identify

Recognized by branched, leafy stems topped with daisy-like heads of violet to blue-purple ray florets around a yellow disk. The leaves are toothed or pinnately cut, and in some species the tips and teeth end in small bristles or spines. The bracts beneath the flower head are arranged in overlapping rows with spreading, often green tips.

Appearance

Size & Dimensions

Height6" - 2'

Width/Spread6" - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~12 weeks

Summer Fall

Flowering occurs from summer into autumn, roughly June to October, with the heaviest bloom following summer rains. The annual tahoka daisy flowers within a few months of germination and continues until frost. Individual heads last one to two weeks.

Detailed Descriptions

Flower Description

violet, blue-purple, or lavender with yellow disk

Foliage Description

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

Annual species flower within months of sowing; perennials mature in one to two years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun on lean, sandy, gravelly, or rocky soils with sharp drainage and a near-neutral to alkaline pH of about 6.5 to 8.0. Established plants withstand heat and drought and need little water, while rich or wet soils shorten their life and cause floppy growth. The annual species are sown directly where they are to grow, as they establish poorly after transplanting. Cool nights and bright sun intensify the flower color. Few pests trouble the genus, though aphids may gather on soft new growth. Many kinds are short-lived and renew from self-sown seedlings.

Pruning

Spent flower heads can be sheared to encourage further bloom and to limit self-seeding in the annual species. Perennial kinds can be cut back after flowering. Leaving some seed heads allows self-sowing for the following year.