Iris kaempferi 'Tsuru no Kegoromo' (Japanese iris) — Clump-forming, upright

Overview

Iris kaempferi 'Tsuru no Kegoromo' 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 kaempferi 'Tsuru no Kegoromo' 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 kaempferi 'Tsuru no Kegoromo' is a clump-forming, upright perennial iris from Japan prized for its seasonal May to July flowering. It has sword-shaped to grassy foliage that is often glaucous, forming upright fans beneath the blooms. Plants suit full sun and will tolerate some light shade when relieved of the hottest afternoon sun. Hardiness is rated H5–H7 (hardy to fully hardy) across much of the UK.

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 kaempferi 'Tsuru no Kegoromo' is a Japanese iris that forms upright, clump-forming fans of sword-shaped leaves and produces its flowering display from May to July. Native origins are Japanese; cultivated forms of this group are grown for their summer blooms and architectural foliage. The leaves are often glaucous, providing a cool, blue-green tone beneath the flowers. Plant it in a sunny spot—south- or west-facing is ideal—but the variety will tolerate some partial shade. Soil should be neutral to slightly alkaline; while bearded irises need sharp drainage, Japanese types including Iris kaempferi generally perform best in loam-based ground that retains moisture. Where free-draining soil dominates, work in plenty of organic matter to improve water retention. Exposure can be exposed or sheltered, so siting is flexible provided roots remain consistently moist rather than bone dry. Hardiness H5–H7 means this cultivar is hardy through most UK gardens. Use it where summer moisture can be assured: a moist mixed border, alongside a stream or a reliably watered garden bed. The upright, glaucous leaf fans form a clean structural backdrop to the May–July flowers, giving the planting a distinct seasonal presence.

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 kaempferi 'Tsuru no Kegoromo' 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 kaempferi 'Tsuru no Kegoromo'

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 kaempferi 'Tsuru no Kegoromo'?

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 kaempferi 'Tsuru no Kegoromo'?

Iris kaempferi 'Tsuru no Kegoromo' prefers full sun; some tolerate partial shade. It suits exposed or sheltered positions.

What soil does Iris kaempferi 'Tsuru no Kegoromo' need?

Iris kaempferi 'Tsuru no Kegoromo' 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 kaempferi 'Tsuru no Kegoromo'?

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 kaempferi 'Tsuru no Kegoromo' hardy in the UK?

Iris kaempferi 'Tsuru no Kegoromo' 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 kaempferi 'Tsuru no Kegoromo'?

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 →