Helianthus giganteus, also known as Tall or Giant Sunflower, is a perennial wildflower native to Michigan. It can reach 8 feet tall and flowers from July to September with a yellow blossom two to three inches wide. It prefers full sun to partial shade, medium to wet soil and will grow in clay, loam, or sand. Giant sunflower is useful for privacy plantings, rain gardens, or naturalizing larger spaces, since it spreads by rhizome. Also a good choice for difficult clay sites, with sturdy, 9-foot root systems that can loosen tough soil.
Giant Sunflower is popular with pollinators of all kinds, providing both pollen and nectar. It is the host plant for several kinds of Checkerspot and Painted Lady butterflies. The fairly large seeds are a popular food for a variety of birds and mammals. This plant often occurs in wetlands and has even been observed used in beaver dams!
The exuberance of insects using this plant attracts spiders, who find a lot of space in these tall plants to build webs. Hummingbirds, who feed their young exclusively on insects, steal insects caught in the spiders' webs, and also use the spider silk to construct their expandable nests.