Agapanthus 'Delft Blue'

RHS Plant Profile

African lily 'Delft Blue'

Herbaceous Perennial

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A deciduous, clump-forming herbaceous perennial with strap-shaped mid-green leaves and sturdy stems which produce panicles of trumpet-shaped, pale violet-blue flowers, with a darker rib down the centre of each petal in the summer

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

1-1.5 metres

Max Spread

0.5-1 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.5-1 metres
Max Height: 1-1.5 metres

Growing Conditions

Chalk Loam Sand

Moisture: Moist but well–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: South–facing or West–facing
Exposure: Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H5

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Amaryllidaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Clump forming
Potentially harmful: Humans/Pets (dogs, cats): 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: Agapanthus are clump-forming perennials with narrowly strap-shaped leaves, evergreen in some species, and erect stems bearing umbels of funnel-shaped blue or white flowers
Name Status: Accepted

How to Grow

Cultivation

Grow in fertile, moist but well-drained soil in full sun. In cold areas mulch in winter. In containers, grow in peat-free, loam-based compost. See agapanthus cultivation

Propagation

Sow seed when ripe or in spring, keep in cold frame whilst small and protect in winter. Divide clumps in Spring every two-three years

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Patio and container plants
Flower borders and beds

Pruning

Cut back in autumn as foliage goes brown. Cut back flower spikes as they go over, unless you want to keep seedheads for winter interest

Pests

May be susceptible to slugs and snails and agapanthus gall midge

Diseases

May be susceptible to a virus