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?
1. Physical removal: Dig or pull out small infestations. Dispose of all plant material at a landfill or refuse transfer station.
Note: large areas of bare soil are ideal for weed to establish. To avoid this, plant or sow desirable species to cover the bare soil.
2. Foliar spray - Apply herbicide using a hand held sprayer/knapsack. Apply a mix of Glyphosate (360 g/L active ingredient) herbicide at 15ml/L + metsulfuron herbicide (600g/kg active ingredient) at 0.4g/L + an organo silicone penetrant at recommended label rate, and thoroughly wet all parts of plant.
Note: Overspray will kill other (desirable) broadleaf plants and has residual activity in the soil which aids in killing below ground parts. Do not use over or near water bodies or wetlands and use only as directed on label.
Tip Work downstream when controlling infestations adjacent waterways to avoid water born fragments re-infesting areas already controlled.
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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