Senecio triangularis
arrowleaf senecio
Overview
Senecio triangularis is a leafy perennial in the aster family, growing 1-5 feet (0.3-1.5 m) tall on erect, often clustered stems from a fibrous-rooted crown. Its hallmark leaves are triangular to arrowhead-shaped, 2-6 inches (5-15 cm) long, sharply toothed, and held evenly up the stem rather than crowded at the base. In summer the stems are topped by open, flat clusters of small yellow flower heads, each 0.5-0.75 inch (12-18 mm) wide with about 5 to 8 short ray florets around a yellow disc. Bees, flies, and butterflies visit the heads, and tufted seeds follow that scatter on the wind. It grows along mountain streams, in wet meadows, seeps, and moist open forest across western North America, from the lowlands well into the subalpine zone. Plants often form leafy stands in consistently moist ground. Like other ragworts, the foliage contains pyrrolizidine alkaloids that are toxic to livestock and to people if eaten. It depends on reliably moist soil and fades quickly where the ground dries out.
Native Range
Native to western North America, from Alaska and western Canada south through the Cascades, Sierra Nevada, and Rocky Mountains to California, Arizona, and New Mexico. It grows along streambanks, in wet meadows, seeps, and moist coniferous forest from low elevations into the subalpine zone. Its range spans much of the mountainous West.Suggested Uses
Senecio triangularis is used in streamside, bog, and wet-meadow plantings and in mountain native and restoration gardens. Its tall leafy stems and summer yellow flowers suit pond edges and moist naturalized areas. It draws a range of summer pollinators in cool, wet sites.How to Identify
Appearance
Size & Dimensions
Height1' - 5'
Width/Spread1' - 2'
Reaches mature size in approximately 2 years
Bloom Information
Flowering comes in summer, roughly July to August, with timing later at higher elevations. The flat clusters of small yellow heads open over several weeks. Tufted, wind-borne seeds follow as the heads dry in late summer.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-8 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