Iris 'Monspur' 'Dorothy Foster' — Clump-forming, upright

Overview

Iris 'Monspur' 'Dorothy Foster' 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 'Monspur' 'Dorothy Foster' 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.

About

Iris 'Monspur' 'Dorothy Foster' is a clump-forming, upright perennial in the iris family that flowers from May to July. Leaves are sword-shaped to grassy and often glaucous, providing architectural foliage outside the bloom period. It prefers full sun on neutral to slightly alkaline soil and tolerates some partial shade. Suitable for exposed or sheltered sites and hardy across most UK conditions.

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 'Monspur' 'Dorothy Foster' is a clump-forming perennial in the Iridaceae with upright growth and sword-like leaves often showing a glaucous bloom. Flowering runs from May to July, giving a sustained display through late spring into midsummer. Specific origin details are not stated here, but the plant habit and seasonal timing suit classic border use. Site selection favours full sun with the option of light afternoon shade; a south- or west-facing aspect will maximise bloom. It grows in loam, chalk or sand and prefers sharply drained conditions where relevant; soil should be neutral to slightly alkaline. Hardiness H5–H7 places it from 'hardy' to 'fully hardy', so it withstands ordinary UK frosts and will tolerate both exposed and more sheltered positions. Plant as part of a sunny mixed border, beside gravel paths or with other summer-flowering perennials where upright clumps can be shown to advantage. Leave the glaucous, sword-shaped leaves in place after flowering to maintain structure through the summer, and remove spent flower stems to keep the clump tidy and to reveal the foliage form.

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 'Monspur' 'Dorothy Foster' size, habit and characteristics

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

Care notes

Pruning and caring for Iris 'Monspur' 'Dorothy Foster'

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 'Monspur' 'Dorothy Foster'?

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 'Monspur' 'Dorothy Foster'?

Iris 'Monspur' 'Dorothy Foster' prefers full sun; some tolerate partial shade. It suits exposed or sheltered positions.

What soil does Iris 'Monspur' 'Dorothy Foster' need?

Iris 'Monspur' 'Dorothy Foster' 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 'Monspur' 'Dorothy Foster'?

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 'Monspur' 'Dorothy Foster' hardy in the UK?

Iris 'Monspur' 'Dorothy Foster' 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 'Monspur' 'Dorothy Foster'?

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 →