Iris laevigata 'Albo-Purpurea' (Japanese Iris) — Clump-forming, upright

Overview

Iris laevigata 'Albo-Purpurea' 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. Iris laevigata 'Albo-Purpurea' 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. It is native to Japan.

About

Iris laevigata 'Albo-Purpurea' is a clump-forming, upright perennial iris from Japan, valued for its May to July flowering. It bears sword-shaped to grassy leaves that are often glaucous in tone. Best grown in full sun, though some light afternoon shade is tolerated. It prefers neutral to slightly alkaline, moisture-retentive soil in a south or west-facing position.

Wikipedia contributors, CC BY-SA 4.0 — Iris laevigata

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

A clump-forming, upright perennial in the Iridaceae, Iris laevigata 'Albo-Purpurea' comes from Japan and reliably flowers from May to July. The cultivar combines the architectural, sword-shaped leaves typical of the species with season-long presence of foliage that is often glaucous in appearance. Site selection should favour full sun where possible, with some tolerance of partial shade. Soil can be loam, chalk or sand, but for Japanese types give preference to moisture-retentive loam at neutral to slightly alkaline pH; the general note that bearded irises need sharply drained mixtures does not apply here. Aim for a south or west-facing aspect; the plant will tolerate exposed or sheltered locations and carries a UK hardiness rating of H5–H7 (hardy to fully hardy). USDA zones are 3–9. Plant as a grouped clump so the upright habit reads clearly in the border, and avoid letting the soil dry out completely through the growing season. Expect erect flowering stems amid the sword-like, often glaucous leaves, with blooms appearing between May and July and the foliage remaining a defining feature through spring and early summer.

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 laevigata 'Albo-Purpurea' size, habit and characteristics

Plant type: Perennial
Habit: Clump-forming, upright
Foliage: Deciduous or evergreen; sword-shaped to grassy, often glaucous
Native to: Japan

Care notes

Pruning and caring for Iris laevigata 'Albo-Purpurea'

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

How do I grow Iris laevigata 'Albo-Purpurea'?

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.

Where is the best place to plant Iris laevigata 'Albo-Purpurea'?

Iris laevigata 'Albo-Purpurea' prefers full sun; some tolerate partial shade. It suits exposed or sheltered positions.

What soil does Iris laevigata 'Albo-Purpurea' need?

Iris laevigata 'Albo-Purpurea' grows best in loam and chalk or sand; sharply drained for bearded kinds soil. It prefers neutral to slightly alkaline soil. Aim for soil that stays well drained; siberian and japanese kinds need moisture-retentive soil.

How do I prune Iris laevigata 'Albo-Purpurea'?

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.

Is Iris laevigata 'Albo-Purpurea' hardy in the UK?

Iris laevigata 'Albo-Purpurea' has an RHS hardiness rating of H5, meaning it is hardy in most of the UK, tolerating -15 to -10°C.

How do I propagate Iris laevigata 'Albo-Purpurea'?

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.

More in the Iris genus

Browse all Iris →