Sunflower Russian Mammoth Seeds – Heirloom Giant Towering Classic

Ontario Grown
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Clear duties overview for US customers at checkout: Grand Seeds covers 50% tariffs on your order!

In Stock - Shipped within 5 days

Contains about 1 gram of seeds

$1.95

SKU: GS-5394-SUN-DT

Free shipping on orders over $50 (in Canada)

Organicly grown

Non GMO

Description

Sunflower 'Russian Mammoth' (Helianthus annuus), also known as Mammoth Russian, is the legendary 19th-century open-pollinated heirloom giant that sets the standard for giant sunflowers. Growing into massive, tree-like single stalks reaching 10 to 14 feet (or more) in height with thick, heavy-duty trunks, it produces huge single flower heads measuring 12 to 20 inches across. The enormous golden-yellow blossoms feature a thick ring of vibrant ray petals surrounding a dense central disk packed with hundreds of plump, striped gray-and-white seeds. Beyond its impressive garden scale, Russian Mammoth is grown for edible seed production, wild bird feeding, living garden architecture, and children's garden projects.

Specifications

Plant Name: Sunflower 'Russian Mammoth' / 'Mammoth Russian' (Helianthus annuus)
Cultivar Type: Heirloom, Open-Pollinated (19th-Century Russian Classic)
Plant Class: Warm-Season Annual Flower & Seed Crop
Color: Classic golden-yellow petals surrounding a massive dark yellow-green to brown seed disk
Plant Characteristics: Giant single-stem growth habit (120–168+ inches tall / 3–4.2+ m), extra-thick woody stalk, broad rough foliage, single massive flower head (12–20 inches wide), heavy seed yield
Suitable Space: Garden backdrops, property borders, living privacy fences, bird-seed gardens, children's garden plots, competition gardens
Season: Midsummer through Autumn (Warm-Season Annual, ~80–100 Days to Seed Maturity)
Best Time for Sowing (Zone 6b): Direct sow outdoors late May once soil temperatures reach at least 18°C (65°F)
all frost danger has passed. Sow seeds 1 inch deep, spaced 12 inches apart,: all frost danger has passed. Sow seeds 1 inch deep, spaced 12 inches apart,
thin to 18–24 inches apart to allow proper root anchorage. Avoid indoor starting unless using deep biodegradable pots, as taproot restriction stunts plant height.: thin to 18–24 inches apart to allow proper root anchorage. Avoid indoor starting unless using deep biodegradable pots, as taproot restriction stunts plant height.
Sunlight: Full Sun (6+ hours direct sunlight daily; maximum light required to support heavy stalks)
Watering Needs: Moderate (requires consistent moisture
heavy feeding during rapid vegetative growth; moderately drought-tolerant once mature): heavy feeding during rapid vegetative growth; moderately drought-tolerant once mature)
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What is included?

Contains about 1 gram of seeds

Check out the growing specs for the specific organic heirloom seeds you bought.

Good to know

Towering size and massive flower heads create high visual impact and serve as excellent living garden structures or privacy walls
Produces high yields of large, nutritious, easily shelled gray-striped seeds for roasting or winter wild bird feed
Rigid, thick woody trunks naturally resist lodging better than smaller-stemmed tall flower varieties

Single-stem habit yields only one flower head per plant—not suitable as a continuous cut-and-come-again bouquet flower
Heavy seed heads can top-heavy bend or lean in severe autumn windstorms, occasionally requiring sturdy staking or perimeter fence support

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