Sigesbeckia orientalis (Eastern St Paul's-wort)

Richard Fuller, no rights reserved (CC0) · iNaturalist

Sigesbeckia spp.

St. Paul's wort

Asteraceae

Tropical and subtropical Asia, Africa, the Americas, and the Pacific

Attracts Pollinators

Native to North America

SunFull Sun – Part Shade

WaterMedium

Overview

Sigesbeckia spp. is a genus of annual herbs in the daisy family, with about eight species distributed across tropical and warm-temperate regions worldwide. Plants form erect, branched stems 12-48 inches (30-120 cm) tall, often covered in glandular hairs. Leaves are opposite, triangular to oval, 1.5-6 inches (4-15 cm) long, with toothed margins and tapering bases. Small yellow flower heads, 0.2-0.4 inch (5-10 mm) across, combine short ray florets with a central disc and sit above spreading, club-shaped bracts tipped with sticky glands. Flowering occurs through summer and fall. The bracts secrete a sticky substance that causes the small dry seeds to cling to fur and clothing, aiding dispersal. As an annual, the plant grows, flowers, and dies within one season, relying on seed to return. It self-sows readily and behaves as a weed of fields, roadsides, and waste ground in warm climates. Several species are used in traditional herbal medicine.

Native Range

Sigesbeckia spp. species are native to tropical and subtropical regions of Asia, Africa, the Americas, and the Pacific, with S. orientalis ranging widely across the Old World tropics. They grow in open, disturbed habitats such as fields, roadsides, clearings, and stream banks, generally on moist, fertile soils at low to middle elevations.

Suggested Uses

Rarely grown ornamentally, Sigesbeckia spp. appears in herb collections and ethnobotanical gardens, where several species are cultivated for medicinal use. The weedy habit and clinging seeds leave it unsuited to mixed borders. It is more often managed as a weed of fields and disturbed ground.

How to Identify

Recognized by opposite triangular leaves with toothed margins and by small yellow flower heads ringed with spreading, club-shaped bracts tipped with sticky stalked glands. Flower heads are 0.2-0.4 inch (5-10 mm) across. The sticky glandular bracts and clinging seeds separate it from similar yellow-flowered annual daisies.

Appearance

Size & Dimensions

Height1' - 4'

Width/Spread8" - 1'6"

Colors

Flower Colors

yellow

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~10 weeks

Summer Fall

Flowering runs through summer and into fall, typically July through October in temperate areas and over a longer span in the tropics. Each head blooms briefly, but a plant produces heads over several weeks as it branches. Sticky seed heads follow and persist into late autumn.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

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 Range5.5 - 7.5(Neutral)

357912

Soil Types

loam sand silt

Drainagemoist

Water & Climate

Water Needs

Medium

Care & Maintenance

Care Guide

Sigesbeckia spp. grows in full sun to part shade on moist, fertile soils and tolerates a range of conditions as a weedy annual. It is raised from seed sown after the soil warms and germinates within one to two weeks. Growth is rapid, and plants self-sow heavily where seed heads ripen. Drought slows growth and shortens the flowering period. Few pests or diseases affect it. Seedlings are removed before flowering to limit spread in cultivated ground.

Pruning

No formal pruning is practiced. Cutting plants back before the sticky seed heads form reduces self-sowing and the spread of clinging seed. Spent plants die after fruiting and are cleared at the end of the season.