Redroot is the name given to a group of 3 closely related Amaranthus species:
- Amaranthus hybridus
- Amaranthus powellii
- Amaranthus retroflexus.
- A fourth species that is similar to redroot is Amaranthus viridis – purple amaranth
Also commonly referred to as “Amaranthus”, these weeds are widely spread throughout New Zealand, and get their name from the reddish colour towards the base of the plant and tap root. They are commonly found in arable crops and can grow up to 1 metre high. All 4 species are summer growing annuals that normally flower between December and February. Flowers are small and spikey and have many short laterals. Seedheads are commonly up to 200mm long and droop downwards from stems. Main stems form numerous short leafy laterals. Leaves are variable in size, oval shaped and usually green, although they turn red in autumn.
There are a number of options for the control of this weed in pasture and other situations.
- New Pasture:
Select* and MCPB Herbicides will provide excellent control without injury to new grass and clover.
Select – 3-4L/ha at the seedling stage, useful suppression at later stages.
MCPB – 4L/ha but must be treated at the seedling stage.
- Established Pasture:
- MCPA and Pasture Kleen* Herbicides can be used. Some temporary suppression of clover may occur.
Pasture Kleen – 1L/ha for seedlings or 2L/ha for small plants
MCPA – 3L/ha on actively growing weeds at the 4-6 leaf stage.
- Spot Spraying:
Tordon* Gold can all be used as a spot spray to control this weed in pasture, established turf and waste areas. Clover will be temporarily removed form the sward.
- Fodder Brassica:
In fodder brassica crops, Radiate* herbicide provides good suppression of this yield suppressing weed without damaging your crop.
Select Herbicide: registered pursuant to the Pesticides Act 1979 No. 5202
MCPB Herbicide: registered pursuant to the Pesticides Act 1979 No. 268
Pasture-Kleen Herbicide: registered pursuant to the Pesticides Act 1979 No. 5106
MCPA Herbicide: registered pursuant to the Pesticides Act 1979 No. 262
Tordon Gold Herbicide: registered pursuant to the Pesticides Act 1979 No. 5660
For a copy of the new Preside brochure see your local farm merchandise store or call Dow AgroSciences on 0800 803939.
*Registered trademark of Dow AgroSciences.