Iris graminea 'Hort's Variety' (Grass-leaved Iris) — Clump-forming, upright

Overview

Iris graminea 'Hort's Variety' 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 graminea 'Hort's Variety' 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 Europe.

About

Iris graminea 'Hort's Variety' is a clump-forming, upright perennial noted for its narrow, sword-shaped to grassy leaves and a plum-scented flower. It flowers from May to July. Leaves are often glaucous and may be deciduous or retained through winter depending on site.

Wikipedia contributors, CC BY-SA 4.0 — Iris graminea

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 graminea 'Hort's Variety' is a clump-forming perennial native to Europe, with narrow, grass-like foliage and a plum-scented flowering period in late spring to midsummer (May to July). The upright habit produces neat tufts of sword-shaped leaves that often show a glaucous bloom. Plant in full sun, though some tolerance of partial shade is possible. It prefers loam, chalk or sandy soils with a neutral to slightly alkaline pH and good drainage; choose sharply drained spots rather than heavy, waterlogged ground. Sitings on a south- or west-facing bank or border will maximise warmth and flowering; the variety tolerates both exposed and sheltered locations. Hardiness is H5–H7 (hardy to fully hardy), so it is suitable for outdoor cultivation across most of the UK. The narrow, blue-green foliage and upright habit suit the front to middle of a sunny mixed border, a gravel bed or a sunny bank where drainage is free. Combine with broader-leaved perennials that take over as the foliage extends after flowering. The plum scent of the blooms is a distinctive, short-lived summer note during its May–July display.

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 graminea 'Hort's Variety' size, habit and characteristics

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

Care notes

Pruning and caring for Iris graminea 'Hort's Variety'

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 graminea 'Hort's Variety'?

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 graminea 'Hort's Variety'?

Iris graminea 'Hort's Variety' prefers full sun; some tolerate partial shade. It suits exposed or sheltered positions.

What soil does Iris graminea 'Hort's Variety' need?

Iris graminea 'Hort's Variety' 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 graminea 'Hort's Variety'?

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 graminea 'Hort's Variety' hardy in the UK?

Iris graminea 'Hort's Variety' 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 graminea 'Hort's Variety'?

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 →