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Helianthus annuus 'Mongolian Giant'

Uniflorus giganteus, Giant Sunflower

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Helianthus annuus 'Mongolian Giant'

Uniflorus giganteus, Giant Sunflower

Availability: Out of stock

Packet Size:3 grams
Average Seed Count:25 seeds


Giant Sunflower 'Mongolian Giant' is a true giant reaching up to 420cm (14ft) tall with one of the largest flowering sunflower seed heads available. The which can achieve up to 45cm (18in) across.
Not suitable for exposed sites and these extremely tall flowers will definitely will need support.

'Mongolian Giant' is one of the largest-seeded sunflower varieties available to gardeners, the plants are ideal to grow to provide food for birds to eat over-winter.
They can be started indoors 3 to 4 weeks before last spring frost or direct-sown outside after all danger of frost has passed to a depth of 0.5cm (¼in).

Sow indoors in early spring, at 13 to 18°C (55 to 65°F) 4 to 8 weeks before planting outside, alternatively, the seed can also be sown directly where they are to flower in mid to late spring. Beware of slugs when they are still young plants and birds stealing the seeds. For continuity, sow a succession of sunflowers every fortnight for six weeks in the early part of the growing season. In a hot summer, each cycle from sowing to blooming will take about 60 days.
Please remember when positioning your sunflower that, though they track the sun when in the budding stage, a mature sunflower will almost always face to the east.

Sowing Indoors:
For early flowers, start indoors as early as February or March, to germinate in about 10 days at 13 to 18°C (55 to 65°F) and plant out in April or May. Use 7.5cm (3in) pots and a good sowing compost. Sow two seeds 25mm (1in) deep per pot. Water and cover with either polythene or bubble plastic to retain the heat, or place pots on a heated bench or in a propagator with the temperature set at 13°C (55°F).
Remove the covers when the leaves appear. Plant seedlings outside when they are large enough to be handled and the root system is well developed. Add garden compost to the soil if it is heavy or infertile.

Sowing Direct:
Plant outside as early as possible to miss heavy frosts, to germinate in about 1 to 3 weeks, in mid-April through mid-May. Sow seed 5cm (2in) deep and spaced 45cm (18in) apart in borders.
Water seedlings regularly and, when growing tall forms, feed sparingly with a liquid fertiliser when 60cm (2ft) high. Over-fertilization can cause stem breakage in the autumn. Avoid splashing water or fertiliser solution on the stems or leaves.

Harvesting Cut Flowers:
For the vase, cut the fresh flowers in the morning just after they open, but wait until the sun has dried the dew. Remove leaves that are low on the stem, leaving just two or three higher up, near the flower's face. Place the flowers in a bucket filled with water, and leave them to stand for several hours in a cool room before placing in a vase.
Use a clean knife, a clean vase and a few drops of bleach in the water to keep it fresh. Change the water every few days. Blooms can last up to a fortnight when kept in water.
Beware of slugs when they are still young plants and birds stealing the seeds.

Harvesting Seed:
To dry sunflower seeds, cut the heads off when they begin to yellow at the back and hang them upside down in a dry location away from rodents and birds. Once dry, rub the seeds off and soak overnight in 4 litres 1 gal) of water with 1 cup of salt in it. Dry in a 250°F oven for 4 to 5 hours and store in an airtight container. The black-seeded varieties are mainly for oil and birdseed. The grey and white-striped varieties are for drying and eating which can be eaten raw or roasted.

The Latin name for Sunflower, Helianthus annuus, is taken from the Greek helios, meaning sun, and anthos, meaning flower. The Sunflower originated from South America and represented the sun to worshiping Aztec people; it was brought to Europe in the late sixteenth century.
Today the Sunflower is grown for crops in the Mediterranean, Eastern Europe, Argentina, India and the USA.

Current Sunflower World Records:
There are three Guinness Book categories for giant sunflowers

The Tallest Plant: 776cm (25ft 5½in) tall by M Heijms Netherlands in 1986.
Measure from the ground to the highest petal on the flower.

The Largest Head: 82cm (32¼in) diameter by Emily Martin in Canada 1983.
Measure from petal tip to the opposite side petal tip.

The Most Flowers: 837 flowers on a single plant by Melvin Hemker, USA in 2001.
This is just simply the task of counting all flower heads.
It's a good idea to tag each flower as you count that branch.

Additional Information

Additional Information

Packet Size 3 grams
Average Seed Count 25 seeds
Family Asteraceae
Genus Helianthus
Species annuus
Cultivar Mongolian Giant
Common Name Uniflorus giganteus, Giant Sunflower
Hardiness Hardy Annual
Flowers Yellow Petals
Natural Flower Time 50 to 70 days
Height Up to 420cm (14ft) tall
Spacing 30 to 60cm (12 to 24in)
Position Full sun for best performance
Germination 5 to 21 days

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