Helianthus Species, Giant Sunflower, Tall Sunflower

Helianthusgiganteus

Family
Asteraceae (ass-ter-AY-see-ee)
Genus
Helianthus (hee-lee-AN-thus)
Species
giganteus (jy-GAN-tee-us)
Synonym
Helianthus alienus
Helianthus borealis
Helianthus subtuberosus
Helianthus validus
Sun Exposure
Full Sun
Foliage
Herbaceous
Height
36-48 in. (90-120 cm)
Spacing
12-15 in. (30-38 cm)
Hardiness
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)
USDA Zone 10a: to -1.1 °C (30 °F)
USDA Zone 10b: to 1.7 °C (35 °F)
USDA Zone 11: above 4.5 °C (40 °F)
Danger
N/A
Bloom Color
Gold (yellow-orange)
Bright Yellow
Bloom Time
Mid Summer
Other Details
Category
Edible Fruits and Nuts
Perennials
Water Requirements
Requires consistently moist soil; do not let dry out between waterings
Foliage Color
Where to Grow
Bloom Characteristics
This plant is attractive to bees, butterflies and/or birds
Bloom Size
Other details
Soil pH requirements
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)
Patent Information
Non-patented
Propagation Methods
By dividing the rootball
From softwood cuttings
From seed; direct sow outdoors in fall
Seed Collecting
Allow seedheads to dry on plants; remove and collect seeds
Remove fleshy coating on seeds before storing
Properly cleaned, seed can be successfully stored
Regional

This plant is said to grow outdoors in the following regions:

Palm Harbor, Florida

Winter Garden, Florida

Valdosta, Georgia

Croton On Hudson, New York

Bend, Oregon

Houston, Texas

Farmington, Utah

Puyallup, Washington

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Gardener's Notes:

2
positives
0
neutral
0
negative
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T
Winter Garden, FL | July 2020 | positive

Really nice sunflower, giant flower if you give enough water and fertillzer. Seed head get so heavy the plant does have a large droop to it.

P
Elmira, NY (Zone 6a) | January 2008 | positive

A very handsome perennial native plant that flowers the first year from seed. Airy, kind of like coreopsis.

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