Giant blooms, delicious harvests
- Impressive height: Tall, sturdy plants can reach 10–12 feet.
- Massive flower heads: Golden blooms can measure up to 14 inches across.
- Edible seeds: Large, richly flavored seeds for home harvesting and snacking.
- Wildlife friendly: Seeds provide food for birds and other wildlife.
- Pollinator attraction: Summer blooms welcome bees and other beneficial pollinators.
- Heirloom variety: An open-pollinated sunflower with generations of garden history.
Growing specifications
- Botanical name: Helianthus annuus
- Plant type: Annual
- Seed type: Heirloom, open-pollinated
- Planting time: After last frost, once soil has warmed
- Planting method: Direct sow outdoors
- Planting depth: ½–1 inch
- Spacing: 18–24 inches apart
- Days to germination: 7–14 days
- Days to harvest: 80–95 days for seeds
- Mature height: 10–12 feet
- Flower head diameter: Up to 14 inches
- Light requirements: Full sun, 8+ hours daily
- Water requirements: Low to moderate; drought tolerant once established
- Growing difficulty: Easy
How to grow Mammoth Grey Sunflowers
- Direct sow: Plant seeds outdoors after the last frost, once the soil has warmed.
- Choose a sunny location: Select a spot receiving at least 8 hours of direct sunlight.
- Allow room to grow: Space plants 18–24 inches apart to accommodate their impressive size.
- Protect tall stalks: Choose a location with some wind protection and stake plants if needed.
- Harvest the seeds: Wait until the back of the flower head turns yellow-brown and seeds are plump and firm.
Growing tip: These towering sunflowers can become top-heavy, especially in storms. Plant in a sheltered location and provide support when needed.
From garden to table and beyond
Mammoth Grey Sunflowers offer a harvest that feeds more than the gardener. Collect the mature seeds for a homegrown snack, save seeds for future planting, or leave some flower heads for visiting birds.
Plant them along a garden border, at the back of a vegetable bed, or in a sunny backyard growing space for a spectacular summer display with a rewarding edible harvest.