Iris ensata 'Major' (Japanese iris 'Major') — Clump-forming, upright

Overview

Iris ensata 'Major' 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. Iris ensata 'Major' 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 ornamental garden plant, water garden edges and borders. It is native to Japan.

About

Iris ensata 'Major' is a clump-forming, upright perennial in the Iridaceae grown for its summer flowering. It typically reaches about 0.6 m and carries sword-shaped, often glaucous leaves. The cultivar favours moist, neutral to slightly alkaline soils and performs best in full sun or light afternoon shade. Flowering in the UK occurs from May to July.

Wikipedia contributors, CC BY-SA 4.0 — Iris ensata

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 ensata 'Major' originates in Japan and belongs to the iris family (Iridaceae); it forms upright clumps of strap-like leaves and is cultivated as an ornamental for pondsides and borders. Plants are perennial and will form lasting clumps given suitable conditions. Place Iris ensata 'Major' where soil remains moisture-retentive through the growing season, avoiding the sharply drained mix used for bearded irises. A loam that holds moisture is ideal, though it will also tolerate chalk or sand if kept damp; aim for neutral to slightly alkaline pH. Give a south- or west-facing position for the best flowering, with full sun being preferred and some tolerance of partial shade. The range H5–H7 means it is classed from hardy to fully hardy in UK terms (equivalent roughly to USDA 3–9), so it will withstand typical winter conditions across most of Britain. Use this iris at water-garden edges, in mixed perennial borders or where a reliable mid-summer display is wanted. Expect upright clumps to reach around 0.6 m and to produce their flowers between May and 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 ensata 'Major' 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
Suggested uses: Ornamental garden plant, water garden edges, borders
Native to: Japan

Care notes

Pruning and caring for Iris ensata 'Major'

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 ensata 'Major'?

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 ensata 'Major'?

Iris ensata 'Major' prefers full sun; some tolerate partial shade. It suits exposed or sheltered positions.

What soil does Iris ensata 'Major' need?

Iris ensata 'Major' 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 ensata 'Major'?

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.

How big does Iris ensata 'Major' grow?

Iris ensata 'Major' reaches a height of 0.6 m.

Is Iris ensata 'Major' hardy in the UK?

Iris ensata 'Major' 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 ensata 'Major'?

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 →