Montbretia
Botanical Name
Crocosmia xcrocosmiiflora
Family
Iridaceae (iris)
Also known as
Crocosmia hybrid (C. aurea x pottsii)
Where is it originally from?
Africa
What does it look like?
Stiff, leafy, clump-forming, evergreen or summergreen perennial with underground rhizomes. Flattened, light brown corms (35 x 15 mm) have a fibrous cover and form 3+ clusters at the stem base. Firm, sword-shaped leaves (90 x 2 cm) all rise from the base, and are erect to curving above, with a conspicuous mid-vein. Flowerheads are tall and zig-zag shaped. Solitary orange to crimson 6-petalled flowers (3 cm, Jan-Feb) develop into 3-sided seed capsules (5 mm long) that are reddish-brown and flat to triangular.
Are there any similar species?
Watsonia, Alstroemeria, Chasmanthe, Aristea, Sparaxis, Ixia, Schizostylis coccinea and many other bulbous species are similar.
Why is it weedy?
Produces few seeds, but corms and rhizomes multiply rapidly and it also grows from fragments. Tolerates frost and heat, damage and grazing, damp, most soils, and moderate shade.
How does it spread?
Soil movement (road graders, fill), vegetation dumping and water movement spreads this weed from roadsides, slips, wasteland and exotic plantations.
What damage does it do?
Competes with groundcovers and small shrubs, and inhibits the establishment of native plant seedings. Specialised low-growing species may be displaced, especially in riparian margins.
Which habitats is it likely to invade?
Most low-growing habitats, open shrubland, open or disturbed forest, streamsides, alluvial river systems, fernland, short tussock, and wetlands.
What can I do to get rid of it?
Work downstream when controlling.
1. Dig out very small sites. Usually futile in large spots as corms resprout. Dispose of corms at a refuse transfer station, or by burning or by deep burial.
2. Spray (full leaf stage): glyphosate (10ml/L) + metsulfuron-methyl 600g/kg (4g/10L + penetrant).
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and directions for the purchase, use and storage of the product, are followed and adhered to.
What can I do to stop it coming back?
Thrives on disturbance as corms and rhizomes readily resprout. Resists fire. Sites regenerating to canopy over 2 m can normally be left alone, and may benefit from thinning where the weed is dense. Follow up 6-monthly. Replant with dense groundcover where appropriate.
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