Scientific Family
Asteraceae
Synonyms
Helianthus nuttallii ssp.nuttallii, H. fascicularis, H. nuttallii ssp.canadensis, H. nuttallii ssp. coloradensis
Plant type
Forbs and Subshrubs
Origin
Native
Lifecycle
Perennial
Similar species
Helianthus grosseserratus, H. giganteus
Height
Often 3 feet, 13 possible
Riparian
Yes
Often branched in the upper plant, forming clumps of tall, sturdy, green to yellowish or sometimes purplish stems. Narrow green leaves are 3 to 8 inches long. Showy, yellow daisy-like flowers grow in clusters of up to 6 at the stem tops.
Slender rhizomes; thickened, fleshy roots; lower leaves opposite, upper usually alternate; ray flowers conspicuous, 10 to 21, about 1 inch long, leaf margins smooth or serrated, bases wedge-shaped; disc and ray flowers yellow, anthers dark brown to black.
Habitat
Found in moist to wet prairies, marshes, swamps, meadows, streambanks, roadsides and open areas.
Plant Community
Riparian
Disturbed Areas
Low elevation
5000
High elevation
9000
Flower Characteristics
1 to 6 flower heads grow at the top of stems. The flower head is about 3-1/2 inches wide. It consists of a golden yellow center with 60 or more tiny tube-like flowers (disc florets) surrounded by 10 to 21 yellow 1 inch strap-shaped flowers (ray florets).
Flower color
Yellow
Flower shape
Daisy or dandelion-like
Tubular
No
First bloom month
August
Last bloom month
September
Flower clusters
Rounded
Leaf and Stem Characteristics
Leaves are opposite on the lower stem and may be alternate on the upper stem, lance-shaped, about 3 to 8 inches long, 1/4 to 1-1/4 inches wide with a rough texture. Leaf margins often slightly toothed but may be smooth. Stems hairless to sparsely hairy.
Leaf type
Simple
Leaf color
Green
Leaf shape
Narrow
Leaf margin
Toothed
Leaves clasp
No
Leaf hairs
Leaves & stems
Spines
No
Fruit and Seed Characteristics
Fruit is narrow, 1-seeded, smooth, 1/8 to 1/4 inch long with 2 thin, flat, dry bristly structures (scales) at the top. Scales are usually about the same size as the fruit itself but may be shorter. Fruit does not open to release the seed when ripe.
Fruit type
Achene
Fruit color
Brown
Seeds require exposure to cold for 4 weeks (stratification) in order to germinate.