1 / 9

Senecio pinnatifolius

pinnate-leaved groundsel

Overview

Senecio pinnatifolius is a variable annual to short-lived perennial herb growing 6-24 inches (15-60 cm) tall, ranging from prostrate coastal forms to erect inland ones. Stems are branched and mostly smooth, arising from a basal rosette. Leaves vary widely across the species: some are deeply lobed or pinnately divided, others narrow and nearly entire, generally 1.2-4 inches (3-10 cm) long and somewhat fleshy in coastal populations. Flower heads are yellow and daisy-like, 0.6-1 inch (1.5-2.5 cm) across, with about 13 ray florets surrounding a central disc, carried in open clusters at the stem tips. Flowering occurs over much of the year with a peak in spring. Seeds are small and cylindrical, each carried on a white pappus that disperses on the wind. The species occupies coastal dunes, headlands, woodland, and disturbed ground, with separate forms recognised in different habitats. As a native groundsel it contains pyrrolizidine alkaloids and is toxic to grazing livestock if eaten in quantity. Plants are short-lived and regenerate readily from seed.

Native Range

Senecio pinnatifolius is native to Australia, occurring in all mainland states from coastal to inland habitats. It grows on sand dunes, rocky headlands, open woodland, grassland, and disturbed roadsides, with recognised forms adapted to coastal, alpine, and inland conditions.

Suggested Uses

Senecio pinnatifolius is grown in coastal, dune-stabilisation, and native plantings, with the prostrate forms used as low cover on sandy banks, spaced 12-18 inches (30-45 cm) apart. The erect forms suit informal native borders and meadow plantings. Its toxicity to livestock limits its use in or near grazing land.

How to Identify

Recognised by yellow daisy heads 0.6-1 inch (1.5-2.5 cm) across with about 13 ray florets, borne in open terminal clusters above variable foliage. Leaves range from deeply pinnately lobed to narrow and entire, often fleshy in coastal plants. Distinguished from the introduced Senecio madagascariensis by its larger heads, variable leaf shape, and a higher, variable number of involucral bracts rather than a consistent count of about 21.

Appearance

Size & Dimensions

Height6" - 2'

Width/Spread8" - 1'8"

Colors

Flower Colors

yellow

Foliage Colors

green

Bloom Information

Bloom Period

~12 weeks

Spring

Flower heads appear over much of the year, with the heaviest flush in spring (September to November) in temperate regions. Individual heads last about 1-2 weeks before setting wind-borne seed. Flowering is reduced in dry summer conditions and resumes after rain.

Detailed Descriptions

Foliage Description

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 Range5.5 - 7.5(Neutral)

357912

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Senecio pinnatifolius grows in full sun in well-drained sandy or gravelly soils, including saline coastal sites for the dune forms. It tolerates wind, salt spray, and dry periods once established, and completes its life cycle within a year or two. Plants self-seed freely, producing volunteer seedlings around the parent. In cultivation it needs little supplementary water beyond the establishment period. The foliage contains pyrrolizidine alkaloids and is toxic to grazing animals. Few pests affect it, though aphids gather on the flower stems.

Pruning

Spent flower heads are trimmed to limit self-seeding where volunteers are not wanted. Whole plants are cut back after flowering to tidy the clump, though the short lifespan means plants are often replaced from seedlings. No structural pruning is required.