Mammoth Gray Stripe is a true giant among sunflowers, reaching 8 to 12 feet tall and producing enormous seed heads that ripen to stunning gray-striped beauty over 70 days. This vigorous heirloom cultivar grows readily with minimal fuss, rewarding gardeners with abundant, edible seeds beloved by both humans and birds. Plant it where it has room to stretch, and it will dominate the late-summer landscape with its commanding presence and regal fade as autumn approaches.
Full Sun
Moderate
2-11
144in H x ?in W
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High
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The sheer scale of Mammoth Gray Stripe stops people in their tracks: plants regularly tower 8 to 12 feet, with seed heads so large they demand respect and support. The seed itself is big and edible, making this as much a pantry plant as an ornamental statement. Direct sown in late spring, it blooms reliably in August and September, and despite its mammoth stature, it thrives in dry conditions and full sun with almost alarming ease.
Mammoth Gray Stripe is grown primarily for its large, edible seeds, which can be harvested and eaten fresh, roasted, or saved for the birds. The dramatic visual impact makes it an equally valuable ornamental choice for late-summer gardens, creating bold vertical accents and natural garden architecture. The seed heads also dry well and can be left standing for wildlife or harvested for dried arrangements.
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Direct sow in late spring, once the danger of frost has passed and soil has warmed. Choose a location where the plants can reach their full 8 to 12 feet without shading other garden areas. Sow seeds directly into the garden soil where you want them to grow.
Harvest Mammoth Gray Stripe seeds when the back of the seed head turns brown and the face begins to fade, typically 70 days after sowing. Cut the entire seed head with a few inches of stem attached and hang it in a warm, dry location to cure. Once fully dry, rub the seed head gently to dislodge the seeds, or allow birds to harvest directly from the standing plant if you prefer.
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“Mammoth Gray Stripe belongs to that lineage of old-fashioned sunflowers bred specifically for giant proportions and edible seed production. The name itself tells the story: gardeners selected for size and for those distinctive gray-striped seed heads that make the variety instantly recognizable. Passed down through generations of seed savers and home gardeners, it remains a testament to the era when ornamental and practical were never considered separate concerns.”