Helianthus giganteus
Giant sunflower, Tall sunflower, Helianthus alienus, Helianthus borealis, Helianthus subtuberosus, Helianthus validus
Helianthus Helianthus
H. giganteus - H. giganteus is a vigorous, upright, deciduous perennial with lance-shaped, dark green leaves and branching, reddish-purple stems bearing hairy, elliptic to lance-shaped, mid-green leaves and loose clusters of bright yellow flowers in summer.
Helianthus giganteus is: Deciduous
Upright, Clump-forming
Bright-yellow in Summer
Mid-green in Spring; Mid-green in Summer; Mid-green in Autumn
Powdery mildew , Sclerotinia diseases Powdery mildew , Sclerotinia diseases
Cut back after flowering.
Divide every 2-4 years to maintain vigour.
Division, Seed
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Helianthus giganteus (Giant sunflower) will reach a height of 3.5m and a spread of 1.5m after 1-2 years.
Add to salads, Architectural, Beds and borders, Containers, Cottage/Informal, Flower Arranging, Wildflower
Grow in moderately fertile, humus-rich, moist but well-drained soil in full sun. Needs long, hot summers to flower well. May need support. Mulch annually with garden compost or well-rotted manure. Site carefully as may be invasive
Chalky, Clay, Loamy
Moist but well-drained
Alkaline, Neutral
Full Sun
South, East, West
Sheltered
Hardy (H4)
We do not currently have companion plants added for this plant.
Helianthus giganteus
Giant sunflower, Tall sunflower, Helianthus alienus, Helianthus borealis, Helianthus subtuberosus, Helianthus validus
Helianthus Helianthus
H. giganteus - H. giganteus is a vigorous, upright, deciduous perennial with lance-shaped, dark green leaves and branching, reddish-purple stems bearing hairy, elliptic to lance-shaped, mid-green leaves and loose clusters of bright yellow flowers in summer.
Canada, Eastern United States
Deciduous
Upright, Clump-forming
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Bright-yellow in Summer
Mid-green in Spring; Mid-green in Summer; Mid-green in Autumn
Powdery mildew , Sclerotinia diseases
Cut back after flowering.
Divide every 2-4 years to maintain vigour.
Division, Seed
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Helianthus giganteus (Giant sunflower) will reach a height of 3.5m and a spread of 1.5m after 1-2 years.
Add to salads, Architectural, Beds and borders, Containers, Cottage/Informal, Flower Arranging, Wildflower
Grow in moderately fertile, humus-rich, moist but well-drained soil in full sun. Needs long, hot summers to flower well. May need support. Mulch annually with garden compost or well-rotted manure. Site carefully as may be invasive
Chalky, Clay, Loamy
Moist but well-drained
Alkaline, Neutral
Full Sun
South, East, West
Sheltered
Hardy (H4)
Zone 9, Zone 8, Zone 7, Zone 6, Zone 5, Zone 4
Helianthus giganteus (Giant sunflower)
African cottom leafworm; Cotton leafworm; Egyptian cotton leafworm; Egyptian cotton worm; Mediterranean climbing cutworm; Meditteranea Brocade; Tobacco cutworm
Spodoptera littoralis
Insect
Absent
2
3
Regulated pest; frequently intercepted with occasional outbreaks which have been successfully eradicated in the UK.
Helianthus giganteus (Giant sunflower)
American serpentine leaf miner; chrysanthemum leaf miner
Liriomyza trifolii
Insect
Absent
2
3
Regulated pest already subject to review at the EU level (2013). Regularly intercepted in the trade.
Our plants are under greater threat than ever before. There is increasing movement of plants and other material traded from an increasing variety of sources. This increases the chances of exotic pests arriving with imported goods and travellers, as well as by natural means. Shoot is working with Defra to help members to do their part in preventing the introduction and spread of invasive risks.
Traveling or importing plants? Please read "Don't risk it" advice here
Suspected outbreak? Click here for contact details to report to the relevant authority.
Date updated: 7th March 2019 For more information visit: https://planthealthportal.defra.gov.uk/
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This plant likes... | Garden match | |
Soil types: | Chalky, Clay, Loamy | Tell us... |
Soil drainage: | Moist but well-drained | Tell us... |
Soil pH: | Alkaline, Neutral | Tell us... |
Light: | Full Sun | Tell us... |
Aspect: | South, East, West | Tell us... |
Exposure: | Sheltered | Tell us... |
Hardiness: | Hardy (H4) | Tell us... |
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