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Herbaceous Perennial

Canna 'Black Knight'

Erect clump-forming perennial to 1.8m tall, with large, bronze to bluish-purple leaves, and very dark red flowers to 8cm across from midsummer to autumn. A good plant for a tropical border

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Ultimate height

1.5–2.5 metres

Time to ultimate height

2–5 years

Ultimate spread

1–1.5 metres

Loam

Sand

Moisture

Moist but well–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

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)

Botanical details

Family: Cannaceae
Native to the UK: No
Foliage: Deciduous
Habit: Columnar upright
Genus: Canna are rhizomatous herbaceous perennials with erect stems bearing ovate leaves, with showy flowers with showy petal-like staminodes and small, coloured petals and sepals, borne in racemes or panicles in summer and autumn
Name status: Accepted

How to grow

Cultivation

Grow in a sheltered site with full sun. Water freely in dry spells and apply a balanced liquid feed monthly. In cold regions, lift the rhizomes in autumn once frost has blackened the foliage and store in barely moist compost in frost-free conditions. In areas that are frost-free or almost so, leave in situ and protect with a deep dry mulch. See canna cultivation for further information

Propagation

Propagate by division of rhizomes in spring

Suggested planting locations and garden types

Architectural
City and courtyard gardens
Cottage and informal garden
Patio and container plants
Sub-tropical
Bedding
Conservatory and greenhouse
Flower borders and beds

Pruning

No pruning necessary, deadhead flowers to prolong flowering

Pests

May be susceptible to slugs and snails, aphids and glasshouse red spider mite

Diseases

May be susceptible to Canna viruses

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