Cyanthillium spp.

little ironweed

Attracts Pollinators Attracts Butterflies Drought Tolerant

Overview

Cyanthillium spp. is a genus of about five annual and short-lived perennial herbs in the daisy family, native to tropical Africa and Asia and now spread through warm regions worldwide as a weed. The most common species, C. cinereum, the little ironweed, forms an erect, branching plant 6-28 inches (15-70 cm) tall with thin stems and small, alternate, greyish-green leaves. Numerous small flower heads, each about 0.2-0.3 inch (5-8 mm) across, carry pinkish-mauve to purple disc florets and open over much of the year in warm climates. Each head matures into a tuft of soft white pappus that carries the small seeds on the wind. The genus grows on disturbed ground, roadsides, fields, and waste places on a wide range of soils, behaving as a fast-cycling pioneer and crop weed. C. cinereum is used in traditional medicine across Africa and Asia. As short-lived warm-climate plants, these herbs are killed by frost and complete their cycle quickly, renewing entirely from abundant wind-blown seed.

Native Range

Cyanthillium spp. is native to tropical Africa and tropical Asia. C. cinereum has spread as a weed through the tropics and subtropics of the Americas, Australia, and the Pacific, growing on disturbed and cultivated ground.

Suggested Uses

Cyanthillium spp. is rarely grown by choice and is encountered mostly as a weed of fields, gardens, and roadsides. C. cinereum is gathered for use in traditional herbal medicine across parts of Africa and Asia. The flowers are a minor nectar source for small bees and butterflies in warm regions.

How to Identify

Identify Cyanthillium spp. by its slender, erect, branching annual habit and small greyish-green leaves on thin stems. The small flower heads carry pinkish-mauve to purple disc florets, with no ray florets, and stand in loose clusters. Each head ripens to a tuft of soft white pappus, and the whole plant has the look of a small, weedy fleabane.

Appearance

Size & Dimensions

Height6" - 2'4"

Width/Spread4" - 1'

Colors

Flower Colors

purple

pink

Foliage Colors

green

Bloom Information

In warm climates Cyanthillium spp. flowers over much of the year, with peaks in the wet season and after rain. The small purple flower heads open in loose clusters and quickly convert to wind-borne seed. In areas with cold winters, flowering is limited to the frost-free months.

Detailed Descriptions

Flower Description

pinkish-mauve to purple

Foliage Description

greyish-green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-10 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 Range5.0 - 7.5(Neutral)

357912

Soil Types

loam sand clay

Drainagewell drained

Water & Climate

Water Needs

Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Cyanthillium spp. grows in full sun on almost any soil, thriving on disturbed, open, and cultivated ground in warm climates. It is a fast-growing pioneer that germinates, flowers, and seeds within a single season, needing no special care. The plants tolerate poor soil and short dry spells but are killed by frost and complete their cycle before cold weather. Abundant wind-blown seed means self-sown seedlings appear readily wherever the ground is bare. As a weed it is managed by removing plants before the seed heads ripen. It has no particular soil or feeding needs and grows wherever warmth and open ground coincide.

Pruning

As a short-lived herb, Cyanthillium spp. needs no pruning. Where it is unwanted, plants are pulled or cut before the flower heads ripen to limit the spread of seed. Cutting back does little else, as the plant simply flowers again from side shoots while warmth lasts.