Silphium asteriscus aka Starry Rosinweed

Silphium asteriscus belongs to the aster family. This wildflower is a perennial: it lives for years. Its names include rosinweed and starry rosinweed. It grows wild in the central and eastern United States. North Carolina forms part of its native range. There, it grows on the coast, in the Piedmont, and in the mountains. Plants can differ a great deal across their range.

Rosinweed grows 2–5 feet [0.61–1.52 metres] tall in gardens. It spreads 1.5–3 feet [0.46–0.91 metres] wide. The main account gives a usual height of about 3 feet [0.91 metres]. This herbaceous plant has green leaves and sheds them with the seasons. The leaves are lanceolate, or shaped like a lance. Most leaves grow in turns along the stems. Some grow in pairs on opposite sides. The source gives two views on leaf hairs. Its main text notes fine hairs; its checklist lists none. The stems have no scent.

Yellow flower heads add color through the summer months. Their pale yellow shade can be close to gold. Each head is about as wide as a silver dollar. The listed bloom time runs from June through September. The main account says the plant looks best in late summer. Fruit forms from July through October. The seeds add interest in fall. Bees and butterflies feed at the flowers. Songbirds may eat the seeds later in the season.

Rosinweed suits beds of native plants and butterfly gardens. It also suits gardens for pollinators, which move pollen between flowers. Its flowers make a clear show and help wildlife. The care record lists sun, partial shade, and deep shade. It lists moist soil and sites that dry out at times. It states that the soil must drain well. The plant stands up to drought and needs little care. Its listed hardiness range spans USDA zones 4 through 8. The source names seed as the best way to start new plants.

Rosinweed has some, but not strong, resistance to deer. Deer may still browse it. The supplied account names no specific pests or diseases. Rosinweed gets its name from the resin in its sap. Native Americans dried the sap and chewed it to freshen breath. That past use does not show it is safe as food in general. The sources do not clearly assess toxicity for people or pets. They give no basis for treating other parts as safe to eat.