Margaret Stanley

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Margaret Stanley
Manaaki Whenua Landcare Research
Mt Albert, Auckland
stanleym_at_landcareresearch.co.nz
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Weed Management
What are the goals of weed management?   Keep
to improve the ecological state of the site in
mind rather than to control weeds
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Replacement Weeds
Disturbance promotes weed invasion. Weeds are
usually faster at colonising bare ground than
natives.
Method of Least Disturbance (MOLD) use the
weed control method that causes the least
disturbance. MOLD principles allows for the
surrounding vegetation to replace the weed.
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Weed Management Programmes

• Weed-led control
• one weed species is controlled throughout the
  site
• usually when there are very small infestations
  of a very invasive weed  

• Site-led control
• all weed species are controlled throughout the
  site
• less chance of replacement weeds invading
• at least control all the weeds that have the
  same growth form/habitat and might be competing
  with each other (e.g. groundcovers and
  low-growing shrubs tradescantia, watsonia, arum
  lily, etc.)

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Weed Management Programmes
Prioritise which weed?
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Weed Management Programmes

• Satellite vs core infestations
• always control the smallest infestations
  (satellite infestations) first and work towards
  the largest (core) infestations.

Satellite infestations have the greater potential
to become bigger, faster. Controlling all the
small satellite infestations is the best way to
contain the weed.
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Weed Management Programmes

• Satellite vs core infestations
• always control the smallest infestations
  (satellite infestations) first and work towards
  the largest (core) infestations.

Satellite infestations have the greater potential
to become bigger, faster. Controlling all the
small satellite infestations is the best way to
contain the weed.
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Know your weed!

• some weed species fruit prolifically only when
  on edges of forest remnants (ie. more light).
  Start control of these species from the edges and
  work in (e.g. wild ginger).
• advice for weeds with re-sprouting fragments is
  start upstream and work down (e.g. tradescantia
  and willow)
• try to control weeds before the fruit/set seed.
  If this is not possible, try to remove
  flowers/fruit (without spreading them!!)

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Follow-up control
It is critical to follow-up any weed control with
surveillance and control of seedlings and the
bits you missed
Removal of mature plants often results in a flush
of seed germination
Follow-up surveillance and control must be done
regularly and persistently you must be in for
the long haul!!
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Monitoring
Monitoring shouldnt be an afterthought!

• Recording this data gives you
• changing trends in weed infestations
• an ability to alter weed management strategies
• some measure of success - evaluation of weed
  control
• an ability to detect new invasions rapidly and
  eradicate the small infestation before it gets
  too big!!

Surveillance for new/small infestations is
critical
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Site Management
Why is this site weedy? Why are conditions
favourable?
Light? Water? Nutrients? Disturbance (bare
ground)?
How can we change site conditions to exclude
weeds or reduce their density/impact?
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Weed Hygiene
Be aware that you could be spreading weeds within
your restoration site!!!
e.g. fragments and seeds on clothes and boots

• try to maintain some sort of hygiene regime
  dont undo all the hard work!!
• check with council on best ways to dispose of
  particular weeds

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Weedy Advice
Regional councils - fact sheets on all the common
weeds in your region contain info on the weed
and the best ways of controlling them (manual,
chemical, biological).   DOCs Weed Manager -
info on conservation weeds and the best ways of
controlling them (manual, chemical,
biological).   Weedbusters - get the local
community more involved
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Weeds Education Website
www.landcareresearch.co.nz/education/weeds
Weeds in New Zealand!
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A Biocontrol programme for tradescantia has
started..