FlowerSunflower
Mammoth Grey Stripe Sunflower
Mammoth Grey Stripe Sunflower is a breathtaking giant annual that reaches 9 to 12 feet tall, crowned with stunning 12-inch blooms striped in grey. Growing in zones 4 through 10, this open-pollinated heirloom matures in 100 to 109 days, rewarding patient gardeners with some of the largest, most resilient flowers North America has to offer. The dramatic scale and distinctive striped petals make it a showstopper in any garden, while its vigorous growth habit and disease resistance to Leaf Spot, Powdery Mildew, and Rust ensure reliable success.
Photo © True Leaf Market
Growing Conditions
USDA Zone
4-10
Sunlight
Full Sun
Water
Moderate
Soil
Well-drained, Moderately Fertile Loam
Growth Stats
114 in
Height
TypeUpright
Spacing
18
Plant Profile
Sunlight
Full Sun
Water
Moderate
Zones
4-10
Size
114in H x ?in W
Growth
—
Care
High
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Highlights
These towering giants command attention with their massive 12-inch flower heads and distinctive grey striping that sets them apart from solid-colored varieties. The plants reach an astonishing 9 to 12 feet tall, making them among the most resilient and fastest-growing sunflowers available. Open-pollinated and non-GMO, Mammoth Grey Stripe seeds remain true to type year after year, giving seed savers a reliable heritage variety to propagate and share.
Common Uses
Mammoth Grey Stripe Sunflowers are grown primarily as ornamental specimens, where their towering height and dramatic striped blooms create spectacular garden focal points and natural screens. The enormous flower heads attract pollinators and can be dried for decoration. Seeds are occasionally harvested for bird feed or as a novelty crop, though ornamental display remains the primary reason gardeners choose this variety.
Growing Timeline
No timeline data available yet for this variety.
Care Instructions
Direct Sow
Direct sow seeds after the last spring frost when soil has warmed. Plant seeds 18 inches apart in rows spaced 18 inches apart, with spacing adjustments possible depending on support system availability. Thin seedlings to the desired spacing if multiple seeds germinate in one spot.
Growing Calendar
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Companion Planting
Pests & Diseases
Ecology & Traits
Scientific Classification
Helianthus annuus
Family
Asteraceae
Genus
Helianthus
Growth Habit
Upright
Native Status
L48 (N)AK (I)HI (I)PR (I)CAN (I)SPM (I)
History & Origin
“Mammoth sunflowers represent some of the oldest cultivated sunflower varieties, developed through generations of selection for maximum size and vigor. These giants have deep roots in North American gardening tradition, where their enormous flower heads and prodigious growth made them prized by both subsistence farmers and ornamental gardeners. The open-pollinated nature of this variety means gardeners can save seeds from their finest plants, maintaining a direct genetic link to sunflowers grown by previous generations.”