Overview
Helianthus longifolius is a bushy, clump forming annual biennial in the genus Helianthus, part of the Asteraceae family, with deciduous foliage. Helianthus longifolius grows best in full sun, and tolerates loam soils and neutral and alkaline pH. Its UK hardiness is rated H5. Suggested uses include wildlife gardens, cottage and informal garden, flower borders and beds and cut flowers.
About
Helianthus longifolius is a bushy, clump-forming annual or biennial cultivar within the Helianthus genus, known for its upright growth and sizable daisy-like flower heads. This deciduous plant thrives in full sun, ideally in a south-facing, sheltered position with moist but well-drained loam soil of neutral to alkaline pH. Hardy to UK zone H5, it is suitable for wildlife gardens, cottage and informal gardens, flower borders, and as cut flowers. Propagation is typically by seed or division, with spring being the season of interest.
Growing conditions
Best soil and position for Helianthus
- Sunlight
- Full sun
- Soil type
- Loam
- Soil pH
- Neutral, Alkaline
- Soil moisture
- Moist but well-drained
- Aspect
- South-facing
- Exposure
- Sheltered
- UK hardiness
- H5
Plant details
Helianthus longifolius size, habit and characteristics
- Plant type
- Annual Biennial
- Habit
- Bushy, Clump forming
- Foliage
- Deciduous
- Suggested uses
- Wildlife gardens, Cottage and informal garden, Flower borders and beds, Cut flowers
Care notes
Pruning and caring for Helianthus longifolius
- Propagation
- Seed, Division
- Pest resistance
- Susceptible to slugs and snails
- Disease resistance
- Susceptible to powdery mildews and sclerotinia diseases
Frequently asked questions
Where is the best place to plant Helianthus longifolius?
Helianthus longifolius prefers full sun. It suits sheltered positions.
What soil does Helianthus longifolius need?
Helianthus longifolius grows best in loam soil. It prefers neutral and alkaline soil. Aim for soil that stays moist but well-drained.
Is Helianthus longifolius hardy in the UK?
Helianthus longifolius has an RHS hardiness rating of H5, meaning it is hardy in most of the UK, tolerating -15 to -10°C.
How do I propagate Helianthus longifolius?
Seed, Division.
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