Overview
Crocosmia pottsii 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 pottsii 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. It is native to South Africa.
About
Crocosmia pottsii is a clump-forming perennial in the iris family with upright foliage that carries arching sprays of summer flowers. Leaves are deciduous, stiff, pleated and sword-shaped, coloured mid to bright green. It flowers from July to September. Plant in a sheltered, south-, west- or east-facing spot in fertile, moisture-retentive loam.
Wikipedia contributors, CC BY-SA 4.0 — Crocosmia pottsii
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 pottsii (family Iridaceae) is a South African perennial that produces straight, pleated leaves from which arching sprays of flowers appear in mid to late summer. It is a clump-forming species valued for its upright habit and the way floral stems rise above the foliage during the flowering season of July to September. Give Crocosmia pottsii full sun to partial shade in a sheltered position, ideally on south, west or east-facing exposures. It prefers fertile, moisture-retentive loam improved with organic matter and a soil that remains moist but drains freely; it will tolerate acid, neutral or alkaline pH. In UK terms the plant ranges from average to very hardy (H4–H6), so in most regions it will overwinter in a protected spot without special measures. Use Potts' montbretia where upright, architectural foliage and summer flowers are wanted: it suits the middle or rear of a sunny perennial border and will contrast with lower-growing perennials. With its pleated sword-shaped leaves and arching flower sprays, it provides a clear summer presence; expect those sprays to appear and stand above the foliage from July to September.
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 pottsii 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
- Native to
- South Africa
Care notes
Pruning and caring for Crocosmia pottsii
- 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 pottsii?
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 pottsii?
Crocosmia pottsii prefers full sun to partial shade. It suits sheltered positions.
What soil does Crocosmia pottsii need?
Crocosmia pottsii 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 pottsii?
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 pottsii hardy in the UK?
Crocosmia pottsii 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 pottsii?
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
- Crocosmia masonorumMontbretia
- Crocosmia × crocosmiiflora 'A. E. Amos'Montbretia
- Crocosmia × crocosmiiflora 'Aurore'Montbretia
- Crocosmia × crocosmiiflora 'Carmin Brilliant'Montbretia
- Crocosmia × crocosmiiflora 'Emily McKenzie'montbretia 'Emily McKenzie'
- Crocosmia × crocosmiiflora 'Firebird'Montbretia
- Crocosmia × crocosmiiflora 'Golden Glory'Montbretia
- Crocosmia × crocosmiiflora 'His Majesty'montbretia 'His Majesty'