Aristea
Botanical Name
Aristea ecklonii
Family
Iridaceae (iris)
Also known as
Blue iris
Where is it originally from?
West and South Africa
What does it look like?
Evergreen, iris-like perennial (<45 cm tall) with woody rhizomes. Sword-shaped, linear leaves (40 cm x 1 cm) are mostly folded in fans with reddish-purple bases that emerge directly from rhizomes, but sometimes leaves can grow from the flattened, slightly winged stems. Numerous loose clusters of 5-7 very fragile deep blue flowers (2 cm diameter) only appearing in bright sunlight (Oct) develop into grooved seed capsules (2 cm long) containing flat, dark red-brown seeds.
Are there any similar species?
Some other Iris species are similar.
Why is it weedy?
Forms dense stands, and seeds and rhizomes are dispersed locally. Tolerates poor to moderate soils and acidic soils, moderate to hot temperatures, full sun to moderate shade, fire, damage and grazing, and low to high rainfall.
How does it spread?
Seeds and rhizomes are spread by water and on road graders, trampers boots and in soil.
What damage does it do?
Forms dense, long-lived stands in open sites and moderate shade, preventing the seedlings of native species from establishing. Opens up the canopy, leading to further invasion by weedy shrubs, vines and grasses.
Which habitats is it likely to invade?
Shrubland, poor pasture, open and disturbed forest (especially kauri), herbfields, bush margins, gumlands, coastlines and rocky and bare land, especially in warmer areas.
What can I do to get rid of it?
1. Physical removal - Hand pull or dig out entire plant - To prevent regrowth ensure all root material is removed and disposed of to refuse.
2. Cut and paste - Cut the stems as close to the ground as possible and cover the entire cut stems with a glyphosate + metsulfuron gel herbicide as soon as possible after cutting.
3. 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 0.3g/L + an organo silicone penetrant such as 'pulse' or 'boost' at 3ml/L 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.
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?
Rhizomes resprout and seed bank reinfests bare ground. Follow up annually. Maintain weed hygiene, especially on tracks.
Images
