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Herbaceous Perennial

Iris ensata 'Angel Mountain'

Japanese water iris 'Angel Mountain'

A clump-forming, upright perennial, to around 1m high in flower, with narrowly sword-shaped, slightly grey-green leaves. Flowers have short, ruffled white standards, and broad white falls brushed with purple

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Ultimate height

0.5–1 metres

Time to ultimate height

2–5 years

Ultimate spread

0.1–0.5 metres

Loam

Clay

Moisture

Moist but well–drained, Poorly–drained

pH

Neutral, Acid

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full sun
Partial shade

Aspect

South–facing or East–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: Iridaceae
Native to GB / Ireland: No
Foliage: Deciduous
Habit: Clump forming
Potentially harmful: Harmful if 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: 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: Accepted

How to grow

Cultivation

Thrives in moist, humus rich, ideally neutral to slightly acid soil. Will tolerate part shade but flowering is best in full sun. Suitable for planting at the edges of ponds and streams, or in a border where the soil does not dry out

Propagation

Propagate by division, see dividing irises for more detailed advice

Suggested planting locations and garden types

Cottage and informal garden
Flower borders and beds

Pruning

Remove spent flower stems after flowering, and any dying foliage in autumn

Pests

May be susceptible to aphids, slugs, snails, thrips and iris sawfly

Diseases

May be susceptible to aphid-borne virus diseases and grey moulds; see Iris diseases

Get involved

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