Weeding Methods

First of all we need to know where the weeds are.  In the beginning they were simply observed and recorded in memories by keen-eyed members.  Later we conducted a long survey of all 800 hectares which included both native and exotic plants.  Today , an industrious scout surveys two or three hectares , ties ribbons onto vegetation at weedy sites and records their positions on a GPS. This innovation saves an enormous amount of time and energy. 
Manual weeding is preferred and it is indeed the method most commonly used by the Friends of Sherbrooke.  Any plant material that is likely to layer if placed on the ground is either hung up in trees, placed on an improvised platform or taken out of the forest in bags.

The spray technique is used occasionally by a licensed member of our team for small weed patches.  However, Parks Victoria or Melbourne Water use contractors for greater areas, particularly of Blackberry, Ivy and Wandering Trad.

Trees, eg holly, sweet pittosporum and sycamore maple are drilled and filled with a suitable herbicide, as are the larger trunks of ivy and cestrum.  Drill holes are generally 8 or 10mm diameter and 15-25mm deep.  In trees they are placed at 50 - 75mm intervals around the base of the trunk or directly in the roots if these can be seen. 

Sounds easy enough doesn`t it? 

Just as an example to show what really needs to be done to get rid of nasty weeds, here are specific instructions on how to deal with Holly.  It has been written by Viv Freshwater (in our Newsletter No 105) and nobody knows better than she does how to kill `em stone dead!


Members of FOSF have had to learn new techniques in recent years to deal with environmental weeds other than English Ivy and Sweet Pittosporum.  This article describes the best technique we have come up with to successfully control Holly infestations. 

  1. The first task is to remove all the non-layered lower branches from the main trunk just above head height.  This is a safety measure to protect your face and eyes.  Holly leaves have extremely sharp points on them, so be extra careful when completing the task.  Always store all cut branches up off the ground to prevent them from taking root. 
  2. The next task is to remove all the layered branches from around the tree.  Cut the branch from the main trunk and carefully pull it away from the tree.  If the soil is moist and friable most of the rooted layers will be easily removed, but sometimes some of the roots will remain in the soil.  These will also need to be removed.  A pair of pliers or a mattock will make the task easier.  All the individual layers must be removed, including the roots. Make sure that you check for branches that run along the ground, but are still attached to the main trunk.  Always clear the leaf litter away from the trunk to ensure that all branches have been severed and removed from the tree.  Any layers that are too large to be removed by hand can be treated as a separate tree later.  Once again, store the cut branches up off the ground. 
  3. When all the layers have been removed, drill holes into the base of the tree about 4 cm apart and fill with full-strength herbicide.  The holes need to be at least 2 cm deep.  Always complete the drill and fill at the same time, taking no longer than 30 seconds to fill the hole with herbicide.  Then treat any large layered trees using the same method.  Use a 12 mm to 14 mm drill bit, depending on the diameter of the tree.  The larger the tree the more herbicide will be required to ensure success.  Large trees can take up to 9 months to completely die.  If the whole tree is not dead by 12 months, check for areas of live bark around the trunk.  It may be necessary to retreat these areas again.  Holly can be a difficult weed to eliminate. 
This method may seem an extremely tedious and time consuming way of dealing with this weed, but unfortunately the nature of Holly is that if it is not treated correctly, that is, removing all the layered branches, it will regrow and your precious volunteer time will have been wasted.  A positive outcome of all this hard work is that the lyrebirds will have many new areas in which to feed, as has been observed in the areas where this technique has been used in Sherbrooke Forest.


Cestrum grows into large thickets in a few years - if allowed of course ! Here`s a before and after pair of photos to give you an idea of what we frequently tackle.  They were taken beside Clematis Creek in September 2004. The Treefern trunk on the left hand side is about 400mm in diameter and some 5m tall.  Note the ivy at the top of the trunk.  We removed the lower branchlets and the roots.  The ivy left at the top will die in a few weeks.

It`s a good idea to scrape and immediately paint with herbicide any significant stems left on the trunk.