The short answer

Quick Answer

Crocosmia (Montbretia) thrives in full sun or partial shade or full shade on chalky, clay soils (pH 6-7.5), free-draining. Reaches 60cm to 1.2m tall depending on cultivar, slowly spreading. Excellent chalk tolerance. Hardy to around -10°C.

Read on for pruning, planting, companions, seasonal care and common problems.

On this page

Pruning

When: Late autumn or early spring

How: Cut all dead stems and leaves to ground level

Origin, history and folklore

Origin: Southern Africa

Native or exotic: Exotic. Has naturalised in parts of the UK, especially the west

History: Hybridised in France in 1880 by Victor Lemoine. 'Lucifer' was bred by Alan Bloom in the UK in 1966 and remains the most popular cultivar

Folklore: In its native South Africa, crocosmia corms were roasted and eaten in times of famine

Fun fact: The name Crocosmia comes from the Greek krokos meaning saffron and osme meaning smell, because the dried flowers smell of saffron when placed in water

Historical medicinal uses: None. Some people get a skin reaction to the corms

Wildlife and biodiversity

Pollinators: Excellent for bees and hummingbird hawk-moths [4][5]

Pollinator ranking: 9 out of 10 (10 means a lot of pollinators, 1 means little) [4][5]

Biodiversity value: 6 out of 10 Medium. Provides late summer nectar[4][5][13]

Seasonal highlight: 7 out of 10 Flowers July to September. Seed heads are decorative into autumn[3][4]

Companion planting and pests

Companion planting: Pairs with pennisetum, helenium and echinacea in hot borders

Pest control: Generally pest free

Common diseases and issues: Corm rot in wet soil, spider mites in dry summers. See RHS Crocosmia page

Invasive note: Crocosmia x crocosmiiflora can be invasive in mild areas, especially west of the UK. Deadhead to prevent self-seeding

CGM care note

Crocosmia 'Lucifer' is the most reliable cultivar for Chiltern gardens. We lift and divide congested clumps every 4 years, otherwise flowering drops off.

Useful resources

Plant relationships, Crocosmia (Montbretia)

How Crocosmia (Montbretia) fits with other plants in a real Chiltern garden, what it works well with, what to avoid, and what to use instead in tricky spots.

Works well with

  • Lavender, attracts pollinators, bees and butterflies will move between them, increasing fruit set on nearby crops
  • Salvia (Perennial Sage), attracts pollinators, bees and butterflies will move between them, increasing fruit set on nearby crops
  • Alliums (Ornamental Onions), attracts pollinators, bees and butterflies will move between them, increasing fruit set on nearby crops
  • Agapanthus (African Lily), attracts pollinators, bees and butterflies will move between them, increasing fruit set on nearby crops
  • Rudbeckia (Black-eyed Susan), attracts pollinators, bees and butterflies will move between them, increasing fruit set on nearby crops
  • Echinacea (Coneflower), attracts pollinators, bees and butterflies will move between them, increasing fruit set on nearby crops

Avoid planting beside

Better choice for exposed sites

Better choice for shade

Replacement for failed box

If box blight has hit your hedges, these are the alternatives we recommend:

Seasonal succession partners

Plants with non-overlapping flowering windows to extend the season:

Relevant services

Related articles

Local projects using this plant

See our portfolio for real gardens where we've used Crocosmia (Montbretia).

Chiltern growing year

12-month care calendar

Use this as a seasonal prompt for this plant. Exact timing depends on species, exposure, soil moisture and the weather in your garden.

JanuaryCheck winter damage and protect vulnerable new growth.
FebruaryPrune only where the plant and weather allow; plan spring work.
MarchRemove winter debris, weed carefully and begin feeding where appropriate.
AprilPlant in workable soil and water new plants during dry spells.
MayMulch before the ground dries and watch for pests and new disease.
JuneKeep new planting watered, stake soft growth and deadhead where useful.
JulyWater deeply during dry Chiltern weather and inspect stressed foliage.
AugustMaintain moisture, remove damaged growth and prune only after flowering when suitable.
SeptemberA good month for planting, dividing and preparing soil for autumn work.
OctoberPlant hardy stock, clear diseased material and add a measured mulch.
NovemberFinish planting before hard frost and check ties, stakes and drainage.
DecemberReview the year, protect exposed plants and plan the next season.

References and justification

The values above for Crocosmia (Montbretia) are supported by the following academic and horticultural authorities. Each reference lists the variables it underpins and the basis for the rating. Inline citation markers (e.g. [4]) next to each value link directly to the supporting reference below.

  1. 1
    RHS (2024). Crocosmia (Montbretia) (Crocosmia x crocosmiiflora and cultivars). Plant Profile. Royal Horticultural Society.

    Confirms the horticultural values above for light, temperature (RHS hardiness rating), water, soil type, pH, drainage, feeding, and pruning times/method for Crocosmia (Montbretia). The RHS is the UK's leading horticultural charity and its plant database is the authoritative reference for garden-worthy species in the British Isles.

  2. 2
    Kew Science (2024). Crocosmia x crocosmiiflora and cultivars. Plants of the World Online. Royal Botanic Gardens, Kew.

    Confirms the botanical classification (family Iridaceae), native geographic origin, and native/exotic status listed above. Kew's POWO is the globally recognised taxonomic authority for vascular plants, maintained by the Royal Botanic Gardens, Kew.

  3. 3
    Goldblatt P, Manning JC (2008). The Iris Family: Natural History and Classification. Timber Press.

    Peer-reviewed phylogenetic/taxonomic study of Iridaceae confirming the origin, taxonomy, and ecological characteristics listed above. Supports: origin, taxonomy, seasonal_highlight, pruning.

  4. 4
    Hicks DM, Ouvrard P, Baldock KCR, et al. (2016). Food for pollinators: quantifying the nectar and pollen resources of urban flower meadows. PLOS ONE, 11(6), e0158117.

    Supports the Pollinator ranking of 9/10 for Crocosmia (Montbretia). The pollinator description above ("Excellent for bees and hummingbird hawk-moths") is consistent with this study's finding that plants in the high-nectar-yield category attract exceptional numbers of bees, butterflies, and moths. The Biodiversity value assessment ("Medium. Provides late summer nectar") is supported by the study's quantification of nectar resources during the mid-summer flowering period (Seasonal highlight: "Flowers July to September. Seed heads are decorative into autumn"). Plants with high floral resources are disproportionately important for sustaining pollinator populations in domestic gardens.

  5. 5
    British Beekeepers Association (2024). Garden Plants for Bees. BBKA.

    Supports the Pollinator ranking of 9/10 and the Pollinators description ("Excellent for bees and hummingbird hawk-moths"). The BBKA maintains the UK's definitive list of pollinator-friendly garden plants, and Crocosmia (Montbretia)'s ranking is consistent with BBKA guidance on bee-attractive species. Also supports the Biodiversity value assessment ("Medium. Provides late summer nectar") in the context of garden-scale pollinator support.

  6. 6
    RHS (2024). Pests and Diseases. Royal Horticultural Society.

    RHS pest and disease database confirms the common diseases, pest control notes, and companion planting observations listed above for Crocosmia (Montbretia). The RHS advisory service is the UK's primary source of evidence-based horticultural pest management.

  7. 7
    RHS (2024). RHS Hardiness Ratings. Royal Horticultural Society.

    The RHS hardiness rating system (H1a-H7) underpins the temperature tolerance value given above. Crocosmia (Montbretia)'s rating is consistent with RHS published hardiness data for the Iridaceae family.

  8. 8
    RHS (2024). Soil Types and Testing. Royal Horticultural Society.

    RHS soil classification and testing guidance supports the soil type, pH range, and drainage requirements listed above for Crocosmia (Montbretia). The RHS advises on soil assessment for all garden plants in the UK.

  9. 9
    GB Non-native Species Secretariat (2024). GB Non-native Species Information Portal.

    The GB Non-native Species Secretariat database confirms the invasive status assessment for Crocosmia (Montbretia). This government-backed portal tracks all non-native species in Great Britain and their ecological impact classification.

  10. 10
    RHS (2024). Pruning Guide: Shrubs and Climbers. Royal Horticultural Society.

    RHS pruning methodology and timing guidance for shrubs and perennials underpins the pruning times and methods listed above for Crocosmia (Montbretia). The RHS assigns plants to pruning groups (1-13) based on flowering time and growth habit.

  11. 11
    RHS (2024). Watering Plants. Royal Horticultural Society.

    RHS watering advice supports the water requirement and drainage values listed above for Crocosmia (Montbretia). The RHS provides evidence-based watering guidance for UK garden conditions.

  12. 12
    RHS (2024). Feeding and Mulching. Royal Horticultural Society.

    RHS feeding and mulching guidance supports the feeding recommendations for Crocosmia (Montbretia). The RHS advises on fertiliser application rates and timing for all garden plant types.

  13. 13
    Bentrup G (2008). Agroforestry: Sustaining native bee habitat for crop pollination. USDA Forest Service, Agroforestry Note 32.

    USDA Forest Service research on companion planting for pollinator habitat supports the companion planting and pest control observations listed above for Crocosmia (Montbretia). This is a peer-reviewed extension publication on agroforestry and biodiversity.

  14. 14
    Royal Botanic Gardens, Kew (2024). Plants Used in Traditional Medicine. Kew Science.

    Kew Science's research on plants used in traditional medicine supports the historical medicinal uses, folklore, and history entries above for Crocosmia (Montbretia). Kew's ethnobotany database is the UK's leading scientific resource on plant use by humans.

Where Crocosmia (Montbretia) performs well locally

Towns where Crocosmia (Montbretia) is well suited to typical local soil and climate conditions.

Excellent and strong match

Suitable with preparation

View all areas we cover