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?
Clear roadsides, tracks and streamsides first, then move into bush.
1. Dig out small patches. Dispose of at a refuse transfer station, burn or bury deeply.
2. Spray (spring-autumn): metsulfuron-methyl 600g/kg (3g) + glyphosate (150ml) + penetrant per 10L water.
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.
