Yarrow
Achillea millefolium
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DESCRIPTION
Yarrow can be found as an erect plant or as a mat but in either case it has an extensive rhizome system. It is a pleasant-smelling perennial with feathery leaves. It can be found with white or sometimes pink flowers atop its flower stalks and can be up to 50cm tall. Individual flowerheads are 5-10mm in diameter as a composite with 4-7 white, pink or red ray type florets and 10-12 white or creams disc florets. Seeds are a flattish grey about 2mm long. The leaves are a feathery, dark green, stalked, lance shaped basal leaves up to 2cm wide and 15cm long. The roots are fibrous which come from the nodes on the rhizome.

HABITAT
Commonly found in pasture, wasteland, lawns and marshy or coastal places. Originally a European native Yarrow can be found throughout New Zealand especially in the drier areas.
It used to be sown as a pasture species in the past because of its tolerance to dry summer conditions and although not so common now is still used in many organic pasture mixes as the deep rhizomes can have higher mineral content than other pasture grasses or clover. As a result, it is often tolerated by farmers but is more of a problem in turf, lawns and waste areas.
MANUAL REMOVAL
Manual control is difficult as the rhizomes can break, and regrowth occurs from each rhizome fragment. Rhizomes will dry and die if left on the surface and can sometimes be killed by burying deep but often there are enough sugars in the rhizome to allow even deeply buried pieces to regrow again.
HERBICIDE CONTROL
Because of the deep and extensive rhizomes Yarrow is hard to kill. Most herbicides give poor control, so it is important to spray in Spring or Autumn. It will take several seasons to completely eradicate.
SPRAY APPLICATION
Selective Control
Ralid is one of the more effective sprays but cannot really be used on lawns anymore. In pasture. Apply to growing foliage. Matted plants will require a second application.
- Boom Spray – 1L/ha.
- Handgun – 100ml/100L.
- Knapsack – 25ml/10L.
GrassMate or TRICLO Herbicide – In lawn or turf. Use in pasture is not on label.
- Boom Spray – 2L/ha.
- Handgun – 250ml/100L.
- Knapsack – 60ml/10L.
In all cases use SuperWetter – 10ml/10L to improve penetration and uptake.
LawnMate – Lawn or turf only
- Boom Spray – 3-4.5L/ha in minimum 200L water.
- Lawnboy or Knapsack – 75-110ml/10L water per 250m2.
Dicamba 500 Select + WHACK – 2,4-D 800 - lawn or turf (same actives as Lawnclean)
- Boom Spray – Dicamba 500 Select - 800ml/ha + WHACK – 2,4-D 800 1kg/ha.
- Knapsack – Dicamba 500 elect 20ml/10L + WHACK – 2,4-D 800 25g/10L sprayed over 250m2.
Non-Selective Control
Glyphosate – while glyphosate can kill Yarrow, it is not particularly effective for control in wasteland areas. If using glyphosate, apply at the following rates and consider adding diflufenican or one of the selective herbicides mentioned above to improve efficacy. Note that glyphosate is non-selective and will kill grass and other desirable vegetation.
- Knapsack or Handgun
- Granny Herbicide – 45g/10L
- G-540 GLYPHOSATE – 66ml/10L
- G-360 GLYPHOSATE – 100ml/10L


