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Herbaceous Perennial

Delphinium elatum 'Sweethearts' (New Millennium Series)

delphinium 'Sweethearts'

A tall and sturdy herbaceous perennial with columns of deep and pale rose pink semi-double flowers to 1.5m or more tall, produced in summer

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Size
Ultimate height
1.5–2.5 metres
Time to ultimate height
2–5 years
Ultimate spread
0.5–1 metres
Growing conditions
Chalk
Clay
Loam
Sand
Moisture
Moist but well–drained, Well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Pink Green
Autumn Green
Winter
Position
  • Full sun
Aspect

South–facing or West–facing or East–facing

Exposure
Sheltered
Hardiness
H5
Botanical details
Family
Ranunculaceae
Native to GB / Ireland
No
Foliage
Deciduous
Habit
Columnar upright
Potentially harmful
Humans/Pets: Harmful if eaten. Wear gloves and other protective equipment when handling. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus

Delphinium can be annuals, biennials or perennials, with palmately lobed basal leaves and showy bowl-shaped flowers in spikes, racemes or panicles

Name status

Accepted

How to grow

Cultivation

Grow in a fertile, well-drained soil in full sun; shelter from strong winds and stake well. For best flower spikes thin shoots when 7cm high to leave a minimum of 2-3 shoots on young plants and 5-7 shoots on established plants. See staking: perennials and delphinium cultivation for further advice

Propagation

Propagate by taking pencil thick basal softwood cuttings in early spring

Suggested planting locations and garden types
  • Cottage and informal garden
  • Flower borders and beds
  • Cut flowers
Pruning

Deadhead by cutting spent flower spikes back to small flowering side shoots. Removing of the flower spikes straight after flowering may encourage a second flush of flowers in late summer. Cut down all growth to ground level after it has withered in autumn

Pests

May be susceptible to aphids, earwigs, delphinium leaf miner, delphinium moth caterpillars, slugs, snails and caterpillars

Diseases

May be susceptible to powdery mildews, delphinium black blotch, crown rot and viruses

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