Helianthus giganteus (Giant Sunflower)

Plant Info
Also known as: Tall Sunflower, Swamp Sunflower
Family:Asteraceae (Aster)
Life cycle:perennial
Habitat:sun; moist woods, marshes, swamps
Bloom season:July - September
Plant height:4 to 10 feet
USDA PLANTS database:Minnesota county distribution map

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Detailed Information

Flower: Flower shape: 7+petals

[photo of flower] Flowers are about 2 to 3 inches across, 10 to 20 petals (ray flowers). The petals are bright to golden yellow; the center is a darker yellow. There are several to many flowers branching off at the top of the plant, each at the end of a stalk less than 4 inches long.

[photo of bracts] The bracts are long, narrow, loose and hairy.

Leaves and stem: Leaf attachment: alternate Leaf attachment: opposite Leaf type: simple

[photo of leaves] Leaves are up to 7 inches long and 2 inches wide, with little or no leaf stem. The texture of the upper side is very rough but the underside is more softly hairy. The edges are finely to coarsly toothed. Attachment is mostly alternate, but the lower leaves may be oppositely attached. The main stem is thick, hairy, and usually reddish or purple.


Giant Sunflower and Sawtooth Sunflower are very similar. Sawtooth Sunflower has a smooth stem that has a white tint, whereas Giant Sunflower has a hairy red stem and hairier leaves. Jerusalem Artichoke is another tall sunflower, but has wider bracts and wider, more finely toothed leaves.

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More photos

Photos taken at Pioneer Park, Blaine, MN, July-August 2008


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Mike - Shoreview, between Lexington & Hodgson on Cty Road J
on: 2011-09-10 09:19:13

There is an artificial pond that was put in to replace wetlands taken for construction about 3/4 mile from Hodgson on CTY Rd J. They planted a full season of beautiful MN wildflowers to bloom every month. The Giant Sunflowers and Prairie Sunflowers are blooming now 9/10/2011.

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