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Products > Helianthus giganteus
Helianthus giganteus - Giant Sunflower

Habit and Cultural Information
Category: Perennial
Family: Asteraceae (Sunflowers)
Origin: North America
Flower Color: Yellow
Bloomtime: Fall
Height: 6-8 feet
Width: 6-8 feet
Exposure: Full Sun
Irrigation (H2O Info): Medium Water Needs
Winter Hardiness: < 0 F
Helianthus giganteus (Giant Sunflower) - A native American herbaceous perennial that produces a several unbranched to few branched slightly hairy reddish square stems up to 8 feet tall that arise from the rhizomatous and spreading base and hold 3 to 5 inch long narrow lanceolate green leaves that undulate slightly with crenate margins. In late summer appear the small 3 inch wide bright yellow sunflowers consisting of 10-20 yellow rays and held in loose clusters at the branch ends. In fall as the flowers fade the drying seed heads are interestingly attractive. Plant is full sun to light shade and give little to regular irrigation - the more you water the bigger it gets. Cut to the ground in late fall or early winter. Hardy into zone 4 (<-20). This wild plant is attractive and fun in the garden. It stays fairly constrained in gardens that are kept fairly dry but where is gets regular irrigation it can be fairly aggressive and spreading, so in irrigated gardens is best where it has room to roam in the back of a border or deep in the meadow. This plant is native to the eastern United States and eastern and central Canada, from Newfoundland west to Alberta south to Minnesota, Mississippi, and South Carolina where it typically is found in valley bottoms in moist soil or wet meadows. We received this plant from John Greenlee and it has grown in our garden for several years - all who see it in the fall are impressed with its tall snaking stems bearing cheery yellow flowers.  The information on this page is based on research conducted in our nursery library and from online sources as well as from observations made of this plant as it grows in our nursery, in the nursery's garden and in other gardens that we have observed it in. We also will incorporate comments received from others and always appreciate getting feedback of any kind from those who have additional information, particularly if this information is contrary to what we have written or includes additional cultural tips that might aid others in growing Helianthus giganteus.