Helianthus giganteus - Giant Sunflower

Family:	Compositae
Habit:	Perennial
Height:	3.6
Synonyms:	H. altissimus. H. decapitalus sulphureus elatior.
Range:	N. America - Maine and Ontario to Saskatchewan, Florida, Louisiana and Colorado.

Helianthus giganteus (Giant Sunflower) is a Perennial which grows to a height of 3.6m . It has a fast growth rate. It has a hardness rating of 4.
Giant Sunflower will flower in March to April. the seeds ripen from April to May
The flowers from this plant are hermaphrodite (has both male and female organs) and they are pollinated by Bees, flies

Soil Information

Giant Sunflower will grow in light (sandy),medium (loamy),hard (clay) soil. It is / is important for the soil to be well drained.
The soil prefers the following PH / acid levels :
- pH of less than 6, Acidic soils
- pH between 6 and 8, Neutral soils
- pH greater than 8, Basic soils
Giant Sunflower prefers moist soils

Ideal Planting Locations

Giant Sunflower should not be planted in shady areas.

Damp or rich thickets, swampy woods and clearings[43].

Planting places suited to this plant described below.

• Grows within a woodland garden
• Grows on a sunny edge
• Can be planted in Cultivated Beds

Cultivation Details

Succeeds in most soils in a sunny position[1]. Requires a rich soil[1]. Dislikes shade[1]. Likes moist soils, doing well by a stream[200]. The young growth is extremely attractive to slugs, plants can be totally destroyed by them[K]. Members of this genus are rarely if ever troubled by browsing deer or rabbits[233]. Plants have a running root system and can be invasive[1].

Edible Uses*

* See disclaimer
Edible Rating: 3/5
Tubers - cooked[95]. A similar taste to Jerusalem artichokes but less productive. The var. 'subtuberosus' is used[1, 177]. Seed - raw or cooked. It can be dried and ground into a powder, then mixed with cornmeal and used for making bread[2, 14, 46, 61, 183]. The seed is very small and fiddly to use[K].

• Root - includes bulbs, corms, tubers, rhizomes etc.
• Seed - includes nuts, cereals, peas and beans.

Medicinal Uses*

* See disclaimer
Medicinal Rating: 0/5
None known

Propagation

Seed - sow spring in a cold frame. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Division in spring or autumn. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring. Basal cuttings in spring. Harvest the shoots when they are about 10 - 15cm long with plenty of underground stem. Pot them up into individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer.

Known Hazards

None known

Other Uses

None known

Cultivars

no recorded cultivars

References

Gray's Manual of Botany.
Fernald. M. L.
Author: Fernald. M. L.
Rating:
Publisher : A bit dated but good and concise flora of the eastern part of N. America.
Date of Publication : 1950

The New RHS Dictionary of Gardening. 1992.
Huxley. A.
Author: Huxley. A.
Rating:
Publisher : Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
Date of Publication : 1992

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