Overview

Iris sibirica 'Wisley White' is a clump-forming, upright perennial in the genus Iris, part of the Iridaceae family, with deciduous or evergreen; sword-shaped to grassy, often glaucous foliage. It typically grows around 0.6 m tall and 0.3 m wide. Iris sibirica 'Wisley White' grows best in full sun; some tolerate partial shade, and tolerates loam and chalk or sand; sharply drained for bearded kinds soils and neutral to slightly alkaline pH. Its UK hardiness is rated H5–H7. Suggested uses include borders, water margins and cottage gardens. It is native to Europe and Central Asia.

About

Iris sibirica 'Wisley White' is a clump-forming, upright perennial prized for its early-summer blooms and narrow, sword-shaped leaves. Plants reach about 0.6 m by 0.3 m, forming neat clumps with glaucous foliage that may be deciduous or evergreen. It suits well-drained neutral to slightly alkaline soils but, as a Siberian-type iris, prefers soil that retains some moisture. Flowering occurs from May to July.

Wikipedia contributors, CC BY-SA 4.0 — Iris sibirica

About the genus

Iris takes its name from the Greek goddess of the rainbow, and for once the naming feels entirely earned. I can't think of another genus that covers so much ground — inky purples, burnt apricots, clean whites, blues that seem lit from inside — or so many situations. There are bearded irises that want their rhizomes baked in full sun, Siberian types happy in ordinary border soil, and species that will sit contentedly at the edge of a pond. What they share is the flower: three petals standing up, three falling away, built with a kind of architectural confidence most plants never attempt. Even out of bloom the foliage earns its place — those upright fans of blue-green leaves hold a border together for months. I grow them for the fortnight in May and June when nothing else in the garden can compete, and I've made my peace with that. Some plants are for the long haul. An iris is an event.

Written by Henry

In the garden

Iris sibirica 'Wisley White' is a cultivar of the Siberian iris, a member of the Iridaceae from Europe and Central Asia. It grows as a clump-forming perennial, producing upright flower stems from a compact crown and a basal fan of grassy, sword-shaped leaves that are often glaucous. Expect a mature plant to be about 0.6 m tall with a 0.3 m spread. Position it in full sun where possible; some specimens will tolerate light afternoon shade. It prefers loam, chalk or sandy soils on a neutral to slightly alkaline pH. Although many irises need sharp drainage, Siberian types benefit from soil that holds some moisture through the growing season rather than becoming bone dry. Aim for a south- or west-facing spot; the species tolerates both exposed and sheltered sites and is classed as hardy to fully hardy in the UK (H5–H7). Use 'Wisley White' in mixed herbaceous borders, at water margins where soil remains reasonably moist, or in cottage-style plantings where its upright habit provides vertical contrast. Its modest spread makes it suitable for planting in groups or edging runs. It flowers from May to July.

Growing conditions

Best soil and position for Iris

Sunlight

Full sun; some tolerate partial shade

Soil type

Loam, chalk or sand; sharply drained for bearded kinds

Soil pH

Neutral to slightly alkaline

Soil moisture

Well drained; Siberian and Japanese kinds need moisture-retentive soil

Aspect

South or west facing

Exposure

Exposed or sheltered

UK hardiness

H5–H7

Plant details

Iris sibirica 'Wisley White' size, habit and characteristics

Plant type

Perennial

Habit

Clump-forming, upright

Foliage

Deciduous or evergreen; sword-shaped to grassy, often glaucous

Height

0.6 m

Spread

0.3 m

Suggested uses

Borders, water margins, cottage gardens

Native to

Europe, Central Asia

Care notes

Pruning and caring for Iris sibirica 'Wisley White'

Cultivation

Plant bearded irises with the top of the rhizome exposed so it can bake in summer sun; beardless kinds sit just below the surface in richer, damper ground. Feed with a low-nitrogen fertiliser after flowering and keep the rhizomes clear of mulch and encroaching neighbours.

Pruning

Remove spent flower stems at the base. Trim the outer leaves back by about half in late autumn to reduce overwintering fungal spores, leaving the central fan intact.

Propagation

Divide rhizomes six to eight weeks after flowering, discarding the old woody centre and replanting vigorous outer sections. Species come from seed, but named cultivars will not come true.

Pest resistance

Generally trouble-free, though iris sawfly and slugs damage foliage and thrips can disfigure buds.

Disease resistance

Prone to leaf spot, and to rhizome rot wherever drainage is poor or planting too deep.

Frequently asked questions

More in the Iris genus

• 
  Iris 'Antigone' (TB)
• 
  Iris 'Dauntless' (TB)
• 
  Iris 'Dipped in Dots' (TB)
• Iris 'Ablaze' (MDB)
• Iris 'After the Storm' (TB)
• Iris 'Aldo Ratti' (TB)
• Iris 'Alene's New Love' (SDB)iris 'Alene's New Love'
• Iris 'Alpine Lake' (MDB)