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Alpine RockeryHerbaceous Perennial

Iris tuberosa

snake's head iris

A tuberous perennial with lance-shaped, glaucous green leaves which appear in winter or early spring. Flowers are borne rather lower than leaf tips, on stems to 40cm, and are a striking combination of greenish-yellow standards with purplish-brown to blackish falls

Other common names
black widow
onion iris
see morewidow iris
Synonyms
Iris hermodactylus tuberosus
Hermodactylus tuberosus

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Size
Ultimate height
0.1–0.5 metres
Time to ultimate height
2–5 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Chalk
Loam
Sand
Moisture
Well–drained
pH
Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green Black Green
Summer
Autumn
Winter Green Black Green
Position
  • Full sun
Aspect

South–facing

Exposure
Sheltered
Hardiness
H5
Botanical details
Family
Iridaceae
Native to the UK
No
Foliage
Deciduous
Habit
Bushy
Potentially harmful
Harmful if eaten. Wear gloves and other protective equipment when handling
Genus

Iris may be rhizomatous or bulbous perennials, with narrow leaves and erect stems bearing flowers with 3 large spreading or pendent fall petals, alternating with 3 erect, often smaller, standard petals, in late winter, spring or early summer

Name status

Correct

Plant range
S Europe

How to grow

Cultivation

Plant tubers 10cm (4in) deep in autumn, in moderately fertile, sharply drained alkaline soil in full sun. Dry summers encourage flowering

Propagation

Propagate by division as soon as the leaves have died back in early summer

Suggested planting locations and garden types
  • Rock garden
  • Wildflower meadow
  • Cottage and informal garden
  • Mediterranean climate plants
  • Low Maintenance
  • Flower borders and beds
  • Banks and slopes
  • Cut flowers
Pruning

No pruning required

Pests

May be susceptible to slugs, snails and thrips

Diseases

May be susceptible to aphid-borne viruses, bacterial soft rot and grey moulds; see Iris diseases

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