Herbaceous perennial sunflowers are generally less taller and more bushier than their giant annual cousins. Although the blooms are smaller, they are more abundant, and flower over a longer period. Helianthus late flowering nature makes it a useful addition for extending the season of colour in the border. For hardy annual forms see Helianthus annuus.
Family: Asteraceae (Daisy family)
Botanical Name: Helianthus
Common Names: Ten-petalled sunflower, thin-leaf sunflower, perennial sunflower, showy sunflower.
Foliage: Deciduous, broadly ovate, mid-green leaves, usually with a rough texture.
Flowers: Bright yellow daisy like flowers with dark centres. Single, double or semi-double forms are available.
Flowering Period: Late-summer to early autumn.
Soil: Any moist but well-drained, alkaline to neutral, good garden soil (sand, chalk or loam). Avoid heavy clay.
Conditions: Full sun. Plant in a south, east or west facing aspect in either an exposed or sheltered position.
Habit: Bushy, upright.
Type: Herbaceous perennial.
Origin: Eastern and Central USA and Canada.
Hardiness: Fully hardy in the UK.
These tough, easy to grow low maintenance perennials are ideal late flowering plants for any garden. Good drought tolerance once established. Ideal for the back of a sunny border.
Plant in any well drained garden soil in a sunny spot, during the autumn or mid spring.
The flowers attract many beneficial insects, such as bees and butterflies.
Helianthus make good long lasting cut flowers and can also be dried successfully for winter decoration.
Water well until established. Support taller varieties with stakes or stout canes.
Regularly dead head faded blooms to keep the plant tidy and encourage further flowering. Divide and replant every three or four years to rejuvenate and maintain vigour.
Cut down stems after flowering, once they die back in the autumn.
Generally pest and disease free. Powdery mildews can affect the flowers in very wet weather.
Sow seed in early to mid spring in a nursery bed. Plant out in late autumn.
Established clumps can be divided when dormant, between autumn and mid spring.
Perennial sunflowers range from tall back of the border specimens to short front border plants:
Helianthus decapetalus produces pale yellow flowers (3in across) from mid-summer onwards. Height to 6ft (1.8m). Good cultivars include: 'Capenoch Star' with lemon yellow flowers, 'Flore Pleno' with double bright yellow blooms, 'Loddon Gold' with fully double golden-yellow flowers and 'Maximus' with single large flowers.
Helianthus Lemon Queen produces masses of large, lemon-yellow, daisy-like flowers from July to September. Height to 6.5ft (2m), spread to 18in (45cm). For sale at Crocus.
Sunflower x laetiflorus produces bright yellow flowers with deep yellow centres. Height: 5-6ft (150-180cm) For sale at Thompson & Morgan.
Helianthus maximiliani (Maximilian Sunflower) is an attractive perennial that produces masses of golden yellow flowers all the way up the tall stems. Available at Thompson & Morgan.
Helianthus salicifolius (willow-leaved
sunflower) is a tall variety with mid green willow-like
leaves that produces sprays of golden yellow flowers
in early autumn. Height to 8ft (2.4m).