Crocosmia X crocosmiiflora

Montbretia

Family: Iridaceae

Origin: Africa

Montbretia with flower stem.
A flowering bulb that dies down in the winter months. Attractive orange flowers has led them to being planted in gardens around NZ.
Photo credit: Su Sinclair

Regional Pest Management Plan (RPMP) status

  • Whole region — Sustained control
  • Hauraki Gulf Controlled Area Notice pest

View more about the RPMP statuses

General description

Clump-forming perennial herb. Leaves are sword-shaped and < 90 cm tall. Flowers are orange, overtop foliage and are borne in January – February.

What you need to know

To help protect our environment:

  • You must not breed, distribute, release or sell montbretia within the Auckland region.
  • You must not plant montbretia within the Auckland region, unless you are transferring an existing plant on your land to another location within the boundaries of the same property.
  • You must destroy any montbretia on land that you occupy if it has been planted in breach of the above rules and you are directed to do so by an authorised person.

Habitats

Riparian margins, roadsides, ditches, wastelands, grassland.

Dispersal

Seeds dispersed by water. Vegetative spread from rhizomes and corms, dispersed by water. Human-mediated dispersal through movement of contaminated soil.

Impact on environment

Forms dense stands and excludes native vegetation.

Control

Site Management

Follow up treated areas 3 times per year. Encourage natural regeneration of native plants or replant treated areas where possible after 2-3 treatments to establish dense ground cover and minimise reinvasion.

Recommended approaches

Physical control

Method: Dig out.

Plant parts requiring disposal: Seeds, rhizomes and corms.

Disposal options: Remove to greenwaste or landfill if practical.

Biocontrol

Biocontrol is currently not available for this species.

Community agrichemical control recommendations

Basic Growsafe certified: Foliar spray with 100ml glyphosate green per 10L of water after flowering.

Certified Handler/Experienced agrichemical user: Foliar spray with 100ml glyphosate green and 4g metsulfuron-methyl per 10L and 20ml penetrant at full leaf stage.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Montbretia Flowerhead showing open blooms and buds.
Best controlled in spring as the bulbs grow with the spring flush. Forms dense clumps on roadsides and can be spread by roadside mowers.
Photo credit: Jonathan Boow