Begonia 'Black Knight' (R)

RHS Plant Profile
begonia 'Black Knight'
begonia 'Black Knight' John Fielding

Synonyms

Begonia 'Midnight'

Herbaceous Perennial Conservatory Greenhouse Houseplants

A rhizomatous tender, evergreen perennial, 35cm high, with large, obliquely heart-shaped, deep burgundy leaves, whose shape is emphasised by a zone near the margin of pale pink and white speckles, and pink flowers from late summer to autumn

Position

Partial shade

Soil Types

Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity
2–5 years
Max Spread
0.1-0.5 metres
Max Height
0.1-0.5 metres

Growing Conditions

Loam Sand
Moisture
Moist but well–drained or Well–drained
pH
Acid or Neutral

Position

Partial shade
Aspect
West–facing or East–facing or North–facing or South–facing
Exposure
Sheltered
Hardiness
H1B

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Begoniaceae
Native to GB/Ireland
No
Foliage
Evergreen
Habit
Bushy
Genus
Begonia can be annuals, evergreen or deciduous perennials or shrubs, with fibrous, tuberous or rhizomatous roots and usually asymmetrical leaves, often strikingly patterned, and small or large flowers, both male and female in the same cluster
Name Status
Accepted
Horticultural Group
Rex begonias are evergreen, rhizomatous perennials grown for their handsome, brightly coloured leaves, rather than the small pale pink or white flowers which may appear in spring, summer or autumn

How to Grow

Cultivation

Grow in light, open, very well-drained, neutral to slightly acidic, peat-free potting compost, and in bright indirect light, at an optimum temperature of 19-23ºC; water moderately when in growth, with balanced liquid fertilizer at alternate waterings; lift tubers in autumn, dry off, and store, then plant again in spring; for more advice, see begonia cultivation (outdoor)

Propagation

Propagate by root cuttings of rhizome sections in summer, or by leaf cuttings in spring or summer in a propagating case, in partial shade

Suggested planting locations and garden types

  • Houseplants
  • Patio and container plants

Pruning

No pruning required

Pests

May be susceptible to caterpillars, mealy bugs, mites, glasshouse thrips, vine weevil and aphids

Diseases

May be susceptible to grey moulds (Botrytis), powdery mildews, stem rot, and rhizome rot