🌻 Helianthus annuus ‘Mongolian Giant’ – Extra Tall Giant Sunflower

‘Mongolian Giant’ is a spectacular, extra-tall sunflower variety producing enormous golden-yellow flower heads with dark centres. This impressive annual creates dramatic vertical impact in gardens and is perfect for the back of borders or as a natural screen.

Highly attractive to pollinators and birds, it produces large seed heads that can be left for wildlife or harvested. The seeds are edible and can be enjoyed raw (after drying) or roasted. An excellent choice for children’s gardens and sunflower-growing competitions.

Key Features

● Extremely tall giant sunflower

● Huge golden-yellow flower heads

● Ideal for borders and garden screens

● Excellent for pollinators and birds

● Edible seeds

● Perfect for competitions and children’s gardens

How to Sow & Grow Sunflower ‘Mongolian Giant’ (UK)

Sow indoors: III–IV (March–April)

Transplant outdoors: V (May) after last frost

Sow directly outdoors: IV–V (April–May)

Flowering period: VII–IX (July–September)

Life cycle: Annual

Germination temperature: 18–22 °C (64–72 °F)

Average germ time: 7–14 days

Depth: 2–3 cm (¾–1¼ in)

Light required: Yes

Moisture: Keep soil moderately moist during germination

Environment: Full sun

Soil type: Fertile, well-drained soil enriched with organic matter

Plant spacing: 45–60 cm (18–24 in)

Height: 250–400 cm (8–13 ft)

Growth habit: Tall, single-stem annual

Sowing & Growing Tips (variety-specific)

● Provide sturdy support in exposed areas due to extreme height.

● Water regularly during dry periods, especially while establishing.

● Feed with a balanced fertiliser during active growth.

● Protect young plants from slugs and snails.

● Leave seed heads to dry fully before harvesting for eating.