Ragwort
Asteraceae - Jacobaea vulgaris
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What does it look like?

Ragwort is a member of the daisy family.  It is an erect, annual to perennial herb and usually grows to 45-70cm tall, but can reach 1.6 metres.  It has reddish-purple stems and wrinkled, divided leaves, which are dark green on top with a downy lining. Leaves appear in a rosette that grows into a dense cluster. Its flowers are bright yellow, and appear in clusters. Downy (fluffy), parachute-like seeds are present. 

Ragwort prefers areas of open space with some area of bare ground for seeds to germinate on, particularly in high rainfall areas.  It will invade open forests, riverbeds, swamps, pastures and coastal areas. It also tolerates a wide range of environmental conditions, except for shade.  Especially abundant in areas of higher rainfall. A well-known pest on dairy farms. Densities of this species have steadily declined in Northland since the introduction of a boiological control, the flea beetle. As such, this species is no longer a significant threat on most properties.

Why is it a problem?

An aggressive, prolific flowering plant that will rapidly colonise in exposed areas, i.e. paddocks. Matures quickly, reduces the productivity of the land and may out-compete native plant seedlings.

 

Control Methods

Always ensure plant is ragwort before treating.

Options:

  1. Weed wipe (spring-summer only): glyphosate (333ml/L + penetrant) or metsulfuron-methyl 600g/kg (5g/L + penetrant) or Tordon Gold (500ml/L).
  2. Spray rosette plants (winter-spring only, before stem formed): 2,4-D (50ml/10 litres (knapsack) or 1-3 litres/ha in 300 litres water (boom spraying)).
  3. Spray: cut any seedheads and dispose of by burning or deep burial, apply glyphosate (100ml/10L knapsack) or metsulfuron-methyl 600 g/kg (5g/10L knapsack) ensuring entire plant is covered.
  4. Granules (all year round): Cut seedheads and dispose of by burning or deep burial, apply Tordon 2G (2g/plant - a half level teaspoon) to the the crushed centre of each plant.
  5. Grubbing or pulling ragwort is best done at full to late flowering stage, when the roots are less likely to regrow. Flower heads of pulled plants should be burned. Damaged plants (from cutting, digging, pugging, mowing or poor spraying) usually regrow, form large additional root crowns (multicrown) and become perennial, ie. flowering annually and not dying. These plants do not respond to 2,4-D herbicide, requiring tougher, more residual herbicides.

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