Senecio inaequidens (Narrow-leaved Ragwort)

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Senecio spp.

groundsels

Asteraceae

Nearly cosmopolitan; all continents except Antarctica

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 4–11

Overview

Senecio spp. is among the largest genera in the family Asteraceae, historically holding more than 1,000 species of annuals, perennials, succulents, shrubs, and climbers known broadly as groundsels and ragworts. Recent taxonomic work has moved many species into segregate genera such as Jacobaea spp. and Curio spp., but a core of roughly 1,000 species remains. Growth forms span low rosettes a few inches high to soft-wooded shrubs 6 feet (1.8 m) tall and trailing succulents with bead-like leaves. Most species carry alternate, often lobed or toothed leaves and clusters of small daisy-like flower heads, typically bright yellow but also cream, orange, red, or purple in some species. The heads measure 0.2 to 1.5 inches (5 to 40 mm) across, with or without spreading ray florets, and ripen into seeds tipped by a soft white pappus that disperses on the wind. Senecio spp. occurs on every continent except Antarctica, in habitats from deserts and high mountains to roadsides and disturbed ground. Many species contain pyrrolizidine alkaloids that are toxic to the liver of livestock, pets, and humans if eaten. Several, including common groundsel (S. vulgaris), are widespread weeds of gardens and farmland that complete several generations a year.

Native Range

Senecio spp. is nearly cosmopolitan, native to every continent except Antarctica and found from sea level to alpine elevations. Centers of diversity lie in southern Africa, the Andes, and the Mediterranean. Species grow in deserts, grasslands, woodlands, wetlands, and heavily disturbed ground.

Suggested Uses

Ornamental Senecio spp. are grown for silver foliage in bedding and containers, for trailing succulent forms in hanging pots, and for yellow daisy bloom in borders and rock gardens, spaced 8 to 18 inches (20 to 45 cm) apart by type. Drought-tolerant species suit gravel and coastal plantings. Weedy groundsels and ragworts are not planted and are managed where they invade pasture.

How to Identify

Most Senecio spp. can be recognized by clustered, small daisy-like heads of yellow florets above alternate, lobed or toothed leaves, with seeds carried on a soft white pappus. A reliable feature is the single row of equal-length involucral bracts at the base of each head, sometimes with a few short bracts below it. Ray florets may be present and spreading or absent, leaving button-like heads. Succulent members are told apart by their fleshy, cylindrical or bead-shaped leaves.

Appearance

Size & Dimensions

Height2" - 6'

Width/Spread6" - 3'

Colors

Flower Colors

red

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~16 weeks

Spring Summer Fall

Flowering time varies widely across Senecio spp.; temperate species bloom from spring through autumn, and weedy annuals such as common groundsel flower nearly year-round in mild climates. The yellow to orange heads measure 0.2 to 1.5 inches (5 to 40 mm) across and open in flat-topped or branched clusters. Many species produce several overlapping generations in one season. Bloom is followed quickly by wind-borne seed.

Detailed Descriptions

Flower Description

yellow, cream, orange, red, or purple

Foliage Description

green to silver-gray, fleshy in succulent species

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 5-12 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 rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Time to Maturity

annuals in weeks; perennials in 1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Because the genus spans many growth forms, conditions differ by species, but most Senecio spp. grow in full sun to light shade and well-drained soil of moderate fertility at a pH of 6.0 to 7.5. Succulent species require a gritty, fast-draining mix and infrequent water, while herbaceous and shrubby species accept average garden moisture. Most tolerate drought once established and decline in waterlogged ground. Hardiness ranges widely: tender succulents are grown indoors or in USDA zones 9 to 11, while temperate perennials survive to zone 4. Aphids and powdery mildew are the usual problems. All parts of many species contain pyrrolizidine alkaloids that damage the liver of grazing livestock and are unsafe in forage.

Pruning

Shrubby and succulent Senecio spp. are trimmed in spring to remove winter-damaged shoots and to shape the plant, and stem tips of trailing succulents are pinched to encourage branching. Herbaceous perennials are cut to the ground after frost. Removing spent flower heads on weedy species before seed sets limits their spread.

Pruning Schedule

early spring