Starry rosinweed (Silphium asteriscus) occurs naturally in flatwoods, sandhills and disturbed areas in the panhandle and along the Gulf coast through Levy county. The common name rosinweed refers to the gummy or resinous substance found in the stems. Native Americans chewed stems to clean their teeth.
Starry rosinweed blooms over a long period of time, producing blooms from spring well into the fall season. It attracts butterflies, bees and other pollinators and is a striking addition to any wildflower garden. The plant will persist in the landscape, although it may die back in the winter, and can reseed on its own. It is fairly drought resistant.
Kidneyleaf rosinweed (Silphium compositum) naturally occurs in sandy uplands throughout much of Florida’s panhandle and south to Pasco County on the west coast. It prefers full sun, but also occurs in open woodlands and woodland edges where it receives less. It produces a deep tap root and will not succeed in areas where this tap root cannot extend (e.g. areas with a shallow confining layer of clay or limestone in the soil) or in areas that stay too wet.
Kidneyleaf rosinweed flowers in July and August in Florida. Flower stalks can reach 6-8 feet in height and often have over a dozen flower heads. It is a wonderful nectar source for butterflies and a seed source for seed-eating songbirds. Its close cousin, starry rosinweed (S. asteriscus), has become widely available to Florida gardeners; kidneyleaf rosinweed has not for some reason. Though its flowers are a bit smaller, it makes up for that in its amazing foliage and exceptional drought tolerance.
Sources:
https://www.fnps.org/plants/plant/silphium-asteriscus
https://flawildflowers.org/flower-friday-silphium-asteriscus/
https://www.fnps.org/plants/plant/silphium-compositum
http://hawthornhillwildflowers.blogspot.com/2009/07/kidneyleaf-rosinweed-silphium.html
