Gladiolus 'Black Star'

RHS Plant Profile
sword lily 'Black Star'

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A cormous perennial, 1m high, with green sword shaped leaves and dramatically deep maroon flowers held on spikes of over 10 flowers that appear from late summer and lasting well into 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
East–facing or 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)
H3

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Iridaceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Columnar upright
Potentially harmful
Ornamental bulbsnot to be eaten. Wear gloves and other protective equipment when handling. Pets: Harmful if eaten. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus
Gladiolus are cormous perennials with fans of sword-shaped or linear leaves and spikes of funnel-shaped flowers
Name Status
Accepted

How to Grow

Cultivation

Grow in fertile, well-drained soil in full sun, planting the corms 15cm deep in spring, on a bed of sharp sand to aid drainage; in frost-prone areas, lift when the leaves turn yellow-brown, and store the new corms in a dry, frost-free place until the following spring; in milder areas, add a thick dry mulch over winter

Propagation

Propagate by division, separating cormlets when dormant

Suggested planting locations and garden types

  • City and courtyard gardens
  • Cottage and informal garden
  • Flower borders and beds
  • Wall side borders
  • Cut flowers

Pruning

No pruning required

Pests

May be susceptible to gladiolus thrip, aphids and slugs

Diseases

May be susceptible to gladiolus corm rot, grey moulds (Botrytis), Fusarium bulb rot, gladiolus core rot, gladiolus dry rot, gladiolus scab and neck rot, fungal leaf spot, and virus diseases