Tithonia spp.

Mexican sunflowers

Asteraceae Mexico and Central America

Attracts Pollinators Attracts Butterflies Attracts Hummingbirds Drought Tolerant Container Friendly

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 9–11

Overview

Tithonia spp. is a genus of about 10 to 15 species of annual herbs, perennials, and soft-wooded shrubs in the family Asteraceae, native to Mexico and Central America. Plants are coarse and fast-growing, reaching 3-10 ft (0.9-3 m) tall with large, often three-lobed leaves 4-12 in (10-30 cm) long on stout, sometimes hollow stems. The daisy-like flower heads are 2-4 in (5-10 cm) across, with ray florets in orange, red-orange, or yellow surrounding a raised disc. T. rotundifolia is an annual grown for its orange-red heads, while T. diversifolia is a tall yellow-flowered perennial that has naturalized across the tropics and is invasive in parts of Africa, Asia, and the Pacific. Flowering runs from summer to autumn, drawing butterflies and other pollinators to the nectar-rich heads. Plants grow rapidly in heat and full sun but are frost-tender and blacken at the first hard freeze. The brittle stems can break in wind on taller species, and rich, wet soil tends to produce foliage at the expense of flowers.

Native Range

Tithonia spp. is native to Mexico and Central America, with the center of diversity in Mexico. Several species extend into the southwestern United States and the Caribbean. T. diversifolia has naturalized widely across tropical Africa, Asia, and the Pacific.

Suggested Uses

Grown in annual borders, cottage gardens, and pollinator and cutting gardens for late-season color. The heads draw butterflies, bees, and migrating hummingbirds, and last well as cut flowers. Taller perennial species are used as fast screens in tropical and frost-free gardens.

How to Identify

Look for tall, coarse herbs or shrubs with large, broadly lobed, sometimes velvety leaves and stout stems. The flower heads resemble single sunflowers or zinnias, 2-4 in (5-10 cm) wide, in orange, red-orange, or yellow with a domed central disc. The swollen, hollow flower stalk just below each head separates Tithonia spp. from true sunflowers.

Appearance

Size & Dimensions

Height3' - 10'

Width/Spread1'6" - 4'

Colors

Flower Colors

orange

red

yellow

Foliage Colors

green

Bloom Information

Bloom Period

~14 weeks

Summer Fall

Flowering begins in midsummer and continues until frost, generally July through October. In frost-free climates T. diversifolia blooms in the cooler months, often November to February. Heads open in succession over many weeks.

Detailed Descriptions

Flower Description

orange, red-orange, and yellow

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 Range6.0 - 7.5(Neutral)

357912

Soil Types

loam sand clay

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

tender

Time to Maturity

3-4 months

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plants grow in full sun and average, well-drained soil with a pH near 6.0 to 7.5, tolerating heat, humidity, and poor soils. Annual species are sown from seed after the last frost and flower within three to four months. Excess water and rich soil produce leafy growth and fewer flowers. Tall species may topple on exposed sites where wind breaks the brittle stems, so they are often staked. Plants are killed by frost, and T. diversifolia regrows from the base where winters stay mild.

Pruning

Pinching young annual plants once branches the stems and increases flower count. Spent heads are removed through the season to prolong bloom and limit self-seeding. T. diversifolia is cut back hard after flowering to manage its size and spread.