How to.

Control weeds

By controlling weeds (i.e. managing, removing or containing) you can protect nearby native plants, animals and ecosystems.

7 Top tips for control:

1. Find out what weeds you're dealing with first. Ask for expert help.
2. Start small. Avoid creating large cleared areas which often allow new and different weeds to establish.
3. Plan your control and work in stages. Tackle outlying weed patches first to slow the rate of weed spread before starting on the worst areas. Replace weeds with natives or non-weedy plants as you go.
4. If your weeds need chemical control, contact Weedbusters Near You to find out the best herbicide to use and how to apply it. You may need permission or qualifications to use herbicide on public land.
5. Destroy weeds before they fruit or seed to prevent a new generation of weeds growing inside your work area.
6. When shifting dead weeds take care not to spread any seeds or fragments around that could grow again.
7. Decide on the best disposal method to use before you start, particularly if working in a large area.
   

Ask for advice on the best method to use for weeds in your particular location before you start work. Contact Weedbusters Near You

Replacing one Problem with Another?

Taking out weeds will often open up the area and offer ideal conditions for other weeds to grow. You've then replaced one problem with another. To stop this happening, it's good to be prepared with a restoration plan.

Some options are to:

• Provide shelter to help existing native seedlings grow.
• Mulch the area and plant rapid-growing natives (such as manuka, coprosmas, wineberry).
• Plant non-invasive exotic plants that will be out-competed by natives in time. Check first whether this is appropriate for the environment.
• Don't plant, but be prepared to revisit the site regularly to control weeds.
• Use selective herbicides so non-weedy plants survive.

The best follow-up method depends on the environment you are working in, so make sure you ask for advice. Your local Department of Conservation office or Regional Council will be able to help.

Controlling: pest shrubs and trees | pest vines | pest herbs and ground cover | pest grasses | pest aquatic weeds

Controlling pest shrubs and trees

Pest shrubs and trees invade forests, riversides, high country, wetlands, and coastlines. They alter natural ecosystems by shading the ground, changing the soil conditions, and displacing native species.

Several methods of control can be used. The one you choose depends on the size of the infestation, and how persistent the species is. Be aware that most pest shrubs and trees will resprout if you simply cut them down.

Non-herbicide control

1. Hand pulling- many seedlings can be pulled out by hand. Try not to disturb the soil more than is necessary or new weed seeds will germinate.
2. Ring-barking -has limited effectiveness as many trees can re-sprout from the base, or heal the wound in their bark ( e.g. sycamore). Ring-barking can be useful for controlling pines.

ring-barking

If you do want to try it, use a sharp chisel, axe or saw to make two parallel deep cuts right around the base of the tree. Make the cuts into the sapwood at least 5cm apart and remove all bark between the cuts.

Herbicide control

1. Cut & Paint Stump treatment - this is the best technique to use for most situations, particularly with smaller trees and shrubs and those that are likely to re-sprout from the base (e.g., wilding pines, elderberry, Darwin's barberry)
   
   First, cut the trunk of the plant close to the ground with a straight flat cut. The cut must be flat so that the herbicide will sit on the cut area.
   
   Then, paint the stump with herbicide within 30 seconds of cutting to get uptake of the herbicide before the sap stops flowing. Use a squeeze bottle or paintbrush to just wet the surface, avoiding excess run-off.
   
   

   darwin's barberry cut

   Vigilant gel is useful for this. It has been especially formulated to kill woody plants without harming the surrounding environment and can be purchased from most garden supply stores. Follow manufacturer's instructions.

   
   
2. Spray - Spraying young plants less than a metre high can be effective. Spray all parts of the plant using a knapsack sprayer or hand gun.

   See tips for spraying .

   For bigger woody plants, use the cut & paint stump method outlined above. It minimises the release of herbicide into the environment while still being effective.

3. Drill (or slash) & inject - Useful for large trees (e.g., crack willow) and shrubs in places where felling would damage the surrounding vegetation. You can use a sheep drench pack and gun, or a plastic squeeze bottle with a long nozzle.
   
   First: Drill holes sloping down into the sapwood at regular intervals around the base of the tree. Alternatively, use a sharp chisel or axe to make deep cuts into the sapwood at regular intervals around the base of the tree.
   
   Don't completely ring-bark the tree as that will reduce the uptake of herbicide.
   
   Then: Place the correct dose of herbicide (see manufacturer's instructions) into each hole or cut as soon as possible.
   
   Note: this method involves leaving dead trees standing, so check for potential danger to people using the area.
   

Controlling pest vines

Weedy vines (e.g. old man's beard, banana passionfruit, Japanese honeysuckle) can cause serious damage to individual trees as well as to the forest canopy. They smother the tree-top; prevent light from reaching the leaves below, and eventually make whole trees collapse.

cut vines

The best way to control vines is to cut the stems, leaving the cut vines up the tree to wither and die well above the ground. Avoid the temptation to pull vines down as you cut the stems otherwise the tree may be damaged.

Cut & Paint Stump method - for single vines

Large infestations sometimes grow from just one or two places in the ground, and are relatively easy to dig out or treat.

First , find the main stem and cut just above the ground

Then, paint the stump with herbicide within 30 seconds of cutting to get uptake of the herbicide before the sap stops flowing. Use a squeeze bottle or paintbrush to just wet the surface, avoiding excess run-off.

A chemical paste or gel works well.

Cut, Wait, Spray method - for large areas of vines

When there are too many plants to treat individually, a second visit is recommended.

First, cut all the vines . Leave cut vines hanging in trees to die off.

Later when the regrowth is a metre long, spray the new foliage.

6 top tips for spraying:

care with spraying

Check the best time of year to apply the spray. Plants usually absorb the most lethal dose of chemical during growth spurts prior to flowering or fruiting. Check you have the correct herbicide for the weed you want to kill. Follow the manufacturer's instructions regarding mixing and application. Do not dip used containers into a water supply, and if you're spraying over or near water, ensure you're using the recommended spray. Add a sticking agent (surfactant) to improve the effectiveness of the spray. You could also consider using marker dye to see where you've been, or a foaming agent to minimise spray drift. Choose fine, calm weather. A very light breeze can help you control the direction of spray drift. Cover new plantings when spraying nearby.

Controlling pest herbs and ground covers

dumping weeds

Pest ground covers and herbaceous plants can smother native plants and prevent native seeds from germinating and growing. Pest plants like wild ginger, montbretia, and tradescantia (wandering jew) are notoriously hard to get rid of and need consistent effort. If you are unlucky enough to have them, here are some options:

1. Dig or Pull treatment - this is appropriate for small infestations.
   
   Make sure you remove all the weed growth from the ground including leaves and underground stems, corms and roots since many pest herbs can grow from small stem fragments (e.g., selaginella, tradescantia).
   
   A variation on this treatment for tradescantia is to roll growth like a carpet to avoid breaking into too many pieces.
   
   Be very careful you don't drop pieces when you move waste material from the site. Put it in a plastic bag and dispose of it carefully.
   
   Keep revisiting the site regularly to pull out any new growth.
   
   
2. Spray - Large infestations may need spraying. See tips for spraying .

Controlling pest grasses

Pest grasses range in size, from the tall and tufted pampas grass, to shorter grasses like Mexican feather grass. Grasses can form dense covers that exclude all other plants.

1. Spray - Spraying is the best option for controlling low grasses. Herbicides are available that kill only grasses, and won't damage other plants.
2. Pull or Grub treatment - Only pull or grub out grasses if you have something to replant in their place, or you are able to go back and control other weed species coming through.
   
   Use a spade or grubber to remove the main root mass, shake off any soil, and leave the roots exposed to die.
   

   Revisit the site regularly to pull or grub any grass re-growth.

   Note: Just cutting grasses won't work because the growing points of grass are too close to the ground to reach.

lagaroshiphon oxygen weed

Controlling aquatic weeds is very difficult. If you do wish to tackle weeds in streams or lakes, ask for expert advice first. The best thing to do is to stop new weeds from reaching waterways. This includes: Cleaning all weed from boating equipment, gear and trailers before moving to another area. Removing all fragments of weed from fishing nets and gear before leaving an area. Emptying aquarium contents onto the compost heap, NOT into or near a waterway or drain.

Useful links for control information:

Overseas: http://www.weedsbluemountains.org.au/control.asp
This site demonstrates control techniques such as stump treating, frilling, drilling, spraying, digging and hand-pulling.