Silphium radula aka Roughleaf Rosinweed

Silphium radula belongs to the aster family, Asteraceae. Its common name is roughstem rosinweed. It is a perennial: it lives for more than two years. Kew gives its native range as the central and east-central United States. That range extends to Mississippi. Kew also lists it as a plant of temperate climates. The Royal Horticultural Society says it is not native to Britain or Ireland. These records give its name and broad range. They say little about where it grows in the wild.

Chicago Botanic Garden says the plant grows upright. The supplied records give no height or width at full size. They thus give no firm size to use in garden plans. They lack details on this species' leaves, stems, and roots. The RHS page describes the genus as a whole. It does not describe this species alone. Those broader traits cannot show the exact form of roughstem rosinweed.

Chicago Botanic Garden lists yellow flowers for this plant. Its bloom entries cover May through June and July through August. Taken together, these give a bloom season of May to August. This does not mean each plant blooms for that whole span. The garden says the plant draws birds and butterflies. The account does not name them or say how they use it. It gives no details on the fruit or seeds.

For garden care, Chicago Botanic Garden lists full sun and partial shade. It gives USDA hardiness zones 6–9. The care record calls for moderate watering. It gives no set plan for when or how much to water. The records do not state soil texture, soil pH, or drainage needs. They give no basis to rate how well it copes with drought. Nor do they give its growth rate. The Chicago page is an archive and gets no more updates.

Chicago Botanic Garden lists beds, borders, and specimen planting as uses. In specimen planting, a plant stands out on its own. Its upright form and yellow blooms suit these roles. The birds and butterflies it draws add to that value. The sources give no pest or disease details for this species. They give no evidence on edible parts, use as medicine, or toxicity. These gaps do not prove that the plant is safe. The records support no firm claim about food use or pet safety.