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Weed Information

Weed Information Sheet

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Aristea

Botanical Name

Aristea ecklonii

Family

Iridaceae (iris) family

Also known as

blue iris

Where is it originally from?

West and South Africa

What does it look like?

Evergreen, iris-like perennial to 45 cm tall with woody rhizomes. Sword-shaped, linear leaves (40 x 1 cm) are folded in reddish-purple-based fans, and are mostly basal but a few are on the flattened, slightly winged stems. Numerous loose clusters of 5-7 very fragile deep blue flowers (2 cm diameter) that only appear in bright sunlight are produced in October and develop into groved 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, 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. Weed wipe (spring-autumn): 1g metsulfuron-methyl 600g/kg + 150ml glyphosate + 10ml penetrant /L.
3. Spray (spring-autumn): 3g metsulfuron-methyl 600g/kg + 150ml glyphosate + 10 ml penetrant /10L.

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.

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