Helianthus mollis aka Ashy Sunflower

Helianthus mollis is a perennial in the aster family. It also goes by ashy sunflower and downy sunflower. It comes from southeastern Canada. Its range also covers the central and eastern United States. Wild plants grow in dry prairies, open woods, and rocky glades. They grow in fields, thickets, and along roads too. This species sheds its leaves at the season's end.

Plants grow upright and spread through rhizomes, forming colonies. Garden plants often grow 2–4 feet [0.61–1.22 metres] tall. RHS gives a top height of about 5 feet [1.5 metres]. Reports give a spread of 0.3–3 feet [0.1–0.91 metres]. Soft hairs coat the stems and grey-green leaves. This pale coat gives the plant its ashy look. The broad, oval leaves can reach 0.5 feet [0.15 metres] long. They have no leaf stalks or clasp the stems. Their bases can be round or shaped like hearts.

Large yellow flowers grow one at a time near stem tops. Their centres are dark. Missouri Botanical Garden gives July to September as the bloom time. Chicago Botanic Garden reports blooms into October. The flowers draw butterflies. Birds feed on the seeds. Goldfinches eat seeds straight from the old flower heads. Leave these heads standing to keep that food within reach. Plants suit meadows and wildlife gardens. They also suit loose groups in borders. They spread, so they fit natural areas better than formal beds.

Give this sunflower full sun and soil that drains well. It can grow in light shade. It also copes with drought and dry ground. Missouri Botanical Garden lists sandy, poor, and rocky soils. It warns against clay, though RHS says clay suits the plant. RHS also favours moist soil. In contrast, American sources describe drier conditions. A site away from strong winds helps stems stay upright. Plants in exposed sites may need stakes. Sources give very different ratings for how much cold plants withstand. Missouri Botanical Garden lists USDA zones 4–9. Chicago lists 2–9. RHS gives the much milder UK rating H2.

Plants need little care, though leaves may look worn by summer. Rust and fungal leaf spots can affect plants. So can powdery mildew. RHS also lists sclerotinia disease. Caterpillars and beetles may chew leaves. Slugs and snails can cause damage too. Sow seed in spring or divide plants in autumn. RHS says to divide plants every three years. This helps them keep growing well.