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Mammoth Russian sunflower seeds grow into extremely tall, vigorous annual plants with thick stems and broad, coarse leaves. This sunflower type is well adapted to warm, sunny climates and requires open garden space to support its height and structure. Plants are commonly grown in garden beds, borders, and large open areas where direct sowing is possible. Seed-grown plants establish reliably in well drained soil and are suitable for general ornamental planting in home gardens.
Features
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Extremely tall, upright annual growth habit
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Suitable for open garden beds and large planting areas
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Adapted to warm and temperate climates
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Performs best in full sun locations
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Establishes well from direct sowing
Specifications
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Scientific name: Helianthus annuus
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Common name (US): Sunflower
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Seed type / variety: Mammoth Russian
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Growth habit: Tall, upright annual
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USDA hardiness zones: 2 to 11 as an annual
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Planting season: Spring
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Sowing season:
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Outdoors: April to June
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Germination time and conditions: 7 to 14 days; warm soil with consistent moisture
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Sunlight requirements: Full sun
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Soil requirements: Well drained, moderately fertile soil
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Watering needs: Regular watering; allow soil surface to dry slightly between waterings
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Mature plant size: 10 to 14 feet tall, 2 to 3 feet spread
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Plant spacing: 18 to 24 inches apart
