Crocosmia × crocosmiiflora (montbretia) — Clump-forming, upright with arching flower sprays

Overview

Crocosmia × crocosmiiflora is a clump-forming, upright with arching flower sprays perennial in the genus Crocosmia, part of the Iridaceae family, with deciduous; stiff, pleated, sword-shaped, mid to bright green foliage. Crocosmia × crocosmiiflora grows best in full sun to partial shade, and tolerates fertile and moisture-retentive loam improved with organic matter soils and acid and neutral or alkaline pH. Its UK hardiness is rated H4-H6. Suggested uses include borders, cut flowers and naturalizing.

About

Crocosmia × crocosmiiflora (Montbretia) is a clump-forming perennial in the iris family that carries upright stems with arching sprays of flowers. Foliage is deciduous, stiff, pleated and sword-shaped in mid to bright green. Flowering runs from July to September, producing deep-orange blooms. Best grown in a sheltered, sunny to partly shaded aspect.

Wikipedia contributors, CC BY-SA 4.0 — Crocosmia × crocosmiiflora

About the genus

Crocosmia, also known as montbretia, is a small genus of flowering plants in the iris family, Iridaceae. It is native to the grasslands of southern and eastern Africa, ranging from South Africa to Sudan. One species is endemic to Madagascar.

Wikipedia contributors, "Crocosmia", CC BY-SA 4.0 — Crocosmia

In the garden

Crocosmia × crocosmiiflora is a clump-forming perennial in the family Iridaceae, valued for its upright stems that bear arching sprays of flowers. Leaves arise from the base and are stiff, pleated and sword-shaped, giving a structural, vertical presence in the border. Flowering takes place from July to September. Plant in full sun to partial shade on a south, west or east-facing site that is sheltered from strong exposure. It prefers a fertile, moisture-retentive loam improved with organic matter and will tolerate acid, neutral or alkaline soils provided they remain moist but well drained. The UK hardiness range is H4–H6 (H4 = average, H5 = hardy, H6 = very hardy), so it will persist across much of the UK when given the recommended siting. Use Montbretia in mixed borders for summer colour, for cutting, or to naturalise in suitable beds. The upright habit and arching flower sprays make it effective placed behind lower perennials or along paths where the orange flowers can be admired at close range. The seasonal display of deep-orange flowers from July to September also provides a reliable source for cutting.

Growing conditions

Best soil and position for Crocosmia

Sunlight: Full sun to partial shade
Soil type: Fertile, moisture-retentive loam improved with organic matter
Soil pH: Acid, neutral or alkaline
Soil moisture: Moist but well drained
Aspect: South, west or east facing
Exposure: Sheltered
UK hardiness: H4-H6

Plant details

Crocosmia × crocosmiiflora size, habit and characteristics

Plant type: Perennial
Habit: Clump-forming, upright with arching flower sprays
Foliage: Deciduous; stiff, pleated, sword-shaped, mid to bright green
Suggested uses: Borders, cut flowers, naturalizing

Care notes

Pruning and caring for Crocosmia × crocosmiiflora

Cultivation: Plant corms in spring rather than autumn, setting them around 10cm deep in ground that holds summer moisture, since drought during bud formation is what produces a poor showing. Clumps become congested within a few years and flowering falls away, so lift and divide regularly. The most vigorous kinds spread strongly and are best kept away from delicate neighbours; in colder gardens a dry winter mulch protects the corms.
Pruning: Remove faded flower stems, or leave the seed capsules for autumn interest. Cut the foliage down once it has yellowed in late autumn, or leave it as crown protection and clear in early spring.
Propagation: Divide congested clumps in spring, separating the chains of corms and replanting the plump upper ones. Species can be raised from seed.
Pest resistance: Little troubled outdoors; red spider mite occurs on plants under glass, and slugs graze new shoots.
Disease resistance: Robust in suitable conditions. Gladiolus rust and corm rot occur occasionally, the latter where drainage is poor.

Frequently asked questions

How do I grow Crocosmia × crocosmiiflora?

Plant corms in spring rather than autumn, setting them around 10cm deep in ground that holds summer moisture, since drought during bud formation is what produces a poor showing. Clumps become congested within a few years and flowering falls away, so lift and divide regularly. The most vigorous kinds spread strongly and are best kept away from delicate neighbours; in colder gardens a dry winter mulch protects the corms.

Where is the best place to plant Crocosmia × crocosmiiflora?

Crocosmia × crocosmiiflora prefers full sun to partial shade. It suits sheltered positions.

What soil does Crocosmia × crocosmiiflora need?

Crocosmia × crocosmiiflora grows best in fertile and moisture-retentive loam improved with organic matter soil. It prefers acid and neutral or alkaline soil. Aim for soil that stays moist but well drained.

How do I prune Crocosmia × crocosmiiflora?

Remove faded flower stems, or leave the seed capsules for autumn interest. Cut the foliage down once it has yellowed in late autumn, or leave it as crown protection and clear in early spring.

Is Crocosmia × crocosmiiflora hardy in the UK?

Crocosmia × crocosmiiflora has an RHS hardiness rating of H4, meaning it is hardy through an average UK winter, tolerating -10 to -5°C.

How do I propagate Crocosmia × crocosmiiflora?

Divide congested clumps in spring, separating the chains of corms and replanting the plump upper ones. Species can be raised from seed.

More in the Crocosmia genus

Browse all Crocosmia →