Tridax spp.

coat buttons

Asteraceae Tropical Americas

Attracts Pollinators Attracts Butterflies Drought Tolerant

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 9–12

Overview

Tridax spp. is a genus of about thirty daisy-family herbs, Asteraceae, native to the warmer parts of the Americas and centred in Mexico. The widely spread coat buttons, T. procumbens, is a low, sprawling to ascending herb 6-20 inches (15-50 cm) tall, with hairy, toothed, roughly arrow-shaped leaves on trailing stems that root at the nodes. Each flower head is held on a long stalk and carries a ring of a few short, creamy-white to pale yellow ray florets, each tipped with three small teeth, around a yellow central disc. The heads close into a fluffy ball of parachute-tipped seeds that scatter on the wind. T. procumbens has spread through the tropics and subtropics worldwide as a weed of crops, lawns, and roadsides, and it is listed as a federal noxious weed in the United States. It seeds heavily and grows year-round in frost-free climates, which underlies both its persistence as a weed and its use in folk medicine across its range. The genus is frost-tender and dies back or dies off where winters are cold. Most species are far less weedy than the well-known T. procumbens.

Native Range

Native to tropical and subtropical America, especially Mexico and Central America, with T. procumbens now spread as a weed through the tropics of Africa, Asia, and Australia.

Suggested Uses

Most species have little ornamental use, and T. procumbens is treated as a weed rather than a garden plant; it is gathered in some regions for traditional medicine and as fodder. A few less weedy species are grown in dry, warm-climate native plantings.

How to Identify

Recognised by hairy, coarsely toothed leaves on sprawling stems and small daisy heads on long stalks, each with only a few broad, creamy ray florets notched into three teeth around a yellow disc. The seed heads form fluffy white balls. The few three-toothed rays and trailing, rooting stems separate Tridax spp. from other small yellow daisies.

Appearance

Size & Dimensions

Height6" - 1'8"

Width/Spread1' - 2'

Colors

Flower Colors

white

yellow

Foliage Colors

green

Bloom Information

Bloom Period

~20 weeks

Summer Fall

In frost-free climates Tridax spp. flowers more or less year-round, with peaks in the warm, wet season. The long-stalked heads open over many weeks and are followed quickly by wind-borne seed. Where winters are cold, flowering runs from summer to autumn.

Detailed Descriptions

Flower Description

creamy-white to pale yellow with a yellow disc

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 Range5.5 - 7.5(Neutral)

357912

Soil Types

sand loam clay

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

tender

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

These are plants of warm climates, growing in full sun in most free-draining soils across a pH of about 5.5 to 7.5, and tolerant of poor and dry ground. Growth is fast and needs little water once established. T. procumbens self-seeds heavily and roots from trailing stems, so it spreads quickly and is hard to remove once settled. The genus is frost-tender and confined to roughly zones 9 and warmer. Seed is the main means of spread, and germination is rapid in warm, moist soil. Because of its weed status, T. procumbens is not grown ornamentally in many regions and is subject to control measures.

Pruning

Pruning is not a normal part of growing these plants. Where any species is kept, trimming back trailing stems and removing seed heads limits self-seeding and rooting. Unwanted plants are pulled before they set seed.

⚠️ Toxicity Warning

Unknown

Perennial

Tridax spp.

coat buttons

Asteraceae Tropical Americas

Attracts Pollinators Attracts Butterflies Drought Tolerant

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 9–12

Overview

Native Range

Native to tropical and subtropical America, especially Mexico and Central America, with T. procumbens now spread as a weed through the tropics of Africa, Asia, and Australia.