Iris laevigata 'Rose Queen' (Japanese Iris) — Clump-forming, upright

Overview

Iris laevigata 'Rose Queen' 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 'Rose Queen' 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 'Rose Queen' is a clump-forming, upright perennial Japanese iris that flowers from May to July. It bears sword-shaped to grassy leaves that are often glaucous and may be deciduous or evergreen. It prefers full sun but will tolerate some light shade and benefits from moisture-retentive soil rather than the sharply drained conditions used for bearded types. Rated H5–H7, it suits most UK gardens where soils remain reasonably moist.

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

Iris laevigata 'Rose Queen' is a Japanese iris in the Iridaceae family, brought to gardens for its concentrated spring–summer display; flowering runs from May to July. The plants form upright clumps with sword-shaped to grassy foliage that often shows a glaucous bloom and may be either deciduous or persist through milder winters. Plant it in a south- or west-facing spot where it will receive full sun or a little partial shade. Soil should be neutral to slightly alkaline and moisture-retentive — loam or heavier soils suit Japanese types better than the sharply drained conditions favoured by bearded irises. Exposure can be either exposed or sheltered, and the cultivar is rated H5–H7 for the UK (hardy to fully hardy), which covers most garden situations; the USDA range 3–9 is a wider international reference. Use Iris laevigata 'Rose Queen' where soil does not dry out through the growing season: moisture-retentive borders and damp beds are appropriate positions. Expect a concentrated display from its clump-forming, upright habit, with flowering from May to July and characteristic sword-shaped, often glaucous leaves.

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 'Rose Queen' 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 'Rose Queen'

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 'Rose Queen'?

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 'Rose Queen'?

Iris laevigata 'Rose Queen' prefers full sun; some tolerate partial shade. It suits exposed or sheltered positions.

What soil does Iris laevigata 'Rose Queen' need?

Iris laevigata 'Rose Queen' 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 'Rose Queen'?

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 'Rose Queen' hardy in the UK?

Iris laevigata 'Rose Queen' 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 'Rose Queen'?

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 →