Agapanthus 'Happy Blue'

RHS Plant Profile

African lily 'Happy Blue'

RHS / Joanna Kossak

Herbaceous Perennial

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'Happy Blue' is an evergreen perennial growing to around 60-70cm tall with dark green, strappy leaves. Flowerheads produce around 35-40 florets per head of light violet-blue flowers from summer onwards, followed by attractive seed heads once the flowers die off in the autumn.

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.5-1 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 or East–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): H3

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Amaryllidaceae
Native to GB/Ireland: No
Foliage: Evergreen
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: Unresolved

How to Grow

Cultivation

In mild areas, grow in well-drained soil in a sunny, sheltered position. Otherwise grow in a container and position in full sun. Water during the growing season and liquid feed monthly from spring to flowering. Overwinter the whole container in a cold greenhouse. See agapanthus cultivation

Propagation

Propagate by division every three to four years in spring

Suggested planting locations and garden types

Patio and container plants
Cottage and informal garden
Flower borders and beds
Cut flowers

Pruning

No need to cut down in the autumn, as the seedheads look attractive over winter

Pests

May be susceptible to slugs and snails and agapanthus gall midge

Diseases

May be susceptible to a virus