How to Grow False Sunflower

Heliopsis helianthoides

Perennial

Heliopsis is a tough, long-flowering perennial that blooms from midsummer into autumn with cheerful yellow daisy-like flowers. Plant in full sun in any well-drained soil. It tolerates drought once established and rarely needs staking unless in rich soil. Cut back hard in late autumn or early spring. Divide every 3-4 years to maintain vigour.

Yearly Lifecycle

JanFebMarAprMayJunJulAugSepOctNovDec

Spring Growth Flowering Growing Leaf Fall

Care Essentials

Spring with a balanced fertiliser. Mulch with compost in autumn.

Watch For

Powdery mildew in dry spells
Aphids on new growth
Slugs on emerging shoots

Companions

Grasses, Echinacea, Rudbeckia, Salvia

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Care Requirements

☀️ Light

Full sun for best flowering

Full sun for best flowering. Tolerates light shade but flowering is reduced and stems may become leggy. Avoid deep shade.

💧 Watering

Drought-tolerant once established

Water during establishment and prolonged dry spells. Once established, heliopsis is remarkably drought-tolerant and rarely needs supplemental water.

🌱 Fertilizing

Light spring feed, avoid over-feeding

Apply a balanced fertiliser in spring as new growth emerges. Avoid over-feeding which causes floppy growth that needs staking.

✂️ Pruning

Chelsea Chop in May, deadhead through summer

Pinch back by a third in late May (Chelsea Chop) for bushier growth. Deadhead regularly for extended bloom. Cut to ground in late autumn or early spring.

Growing Tips

Chelsea Chop for sturdier stems

Heliopsis rarely needs staking in average soil. In rich, moist soil stems may flop — pinch back by a third in late May to encourage bushier, self-supporting growth.

Deadhead for months of bloom

Deadhead regularly to extend flowering well into autumn. Once you stop deadheading, seed heads form quickly.

Divide to maintain vigour

Divide congested clumps every three to four years in spring. Heliopsis spreads steadily and benefits from regular division to prevent die-out in the centre.

Best cultivars for UK gardens

'Summer Sun' (Sommersonne) is the most reliable cultivar for UK gardens — compact, floriferous, and long-lived. 'Loraine Sunshine' has striking variegated foliage.

Pests & Diseases

Pest Aphids

Identification: Clusters of green or black insects on shoot tips and flower buds; sticky honeydew on leaves

Organic treatment:

Blast off with a jet of water
Encourage ladybirds and hoverfly larvae

Chemical treatment:

Fatty acid spray for heavy infestations

Pest Slugs and Snails

Identification: Irregular holes in young leaves; slime trails around plants

Organic treatment:

Copper tape or wool pellets around crowns in early spring
Beer traps or hand-picking at dusk

Chemical treatment:

Ferric phosphate slug pellets scattered thinly around emerging growth

Disease Powdery Mildew Golovinomyces cichoracearum

Symptoms: White powdery coating on leaves, usually starting on lower foliage during dry spells with cool nights

Treatment: Remove badly affected leaves. Improve air circulation by thinning crowded clumps.

Prevention: Space plants well. Water at the base. Divide congested clumps regularly.

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