Friends of Sturt Gorge

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Home / Activities / Bushcare / Weed Control

Weed Control...

Over the years numerous weeds have been introduced which the Friends seek to remove.

List of weeds found in the park
The Bushland Weeding Code
Weed Removal Techniques
Weeds and Fire
Weed Identification


Weed Identification:

The following books are useful in identifying plants:

It’’s Blue with Five Petals (in our library): fantastic resource, you only need to know a plant’s flower colour and number of petals, and there are scale bars.  Grasses are not included

Plants of the Mount Lofty Ranges and Adelaide Region (in our library): excellent, but you need to know which family a plant is in to find the page it is on, or you can look through each of the colour plates. There are no scale bars.

Grass identification manual for everyone: is what it suggests and is very useful.

Stop Bushland Weeds (in our library), which has the common weeds and notes on the native plants they can be confused with.

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The  Bushland Weeding Code:

This article has been taken from Stop Bushland Weeds: A Guide to Successful Weeding in South Australias Bushland by Meg Robertson and published by The Nature Conservation Society of South Australia 1994.

Look before you weed - know where the native plants are.

Choose the most effective and selective weeding technique for the plant and the location.

Adapt to the season and weather conditions. Don’t pull or grub weeds when the soil is dry and roots break off when pulled, or tramp through when soil is so soft that your feet damage plants at each step.

Minimise the amount of trampling over the site and scatter the team of workers so that they do not form a new trail. Wear soft-soled shoes and clothes which do not carry weed seeds or drag on foliage. Wear gloves.

Before you pull, grub or poison large weeds, pull the small weeds which are growing underneath them.

Avoid damage to native plants. Dont drop or fell large weeds onto native plants or drag boughs through the bush.

Disturb soil as little as possible. Replace any disturbed soil, press it down and replace leaf litter.

Remove from the bush any parts of weeds which could regrow: ripe seeds, seed heads, bulbs, rhizomes and runners. Break up the rest into small pieces and leave them scattered to form a mulch, especially over the spots where weeds have been removed.

Do follow up work before moving on to weed a new area.

Remove weed seeds or bulbils which could scatter into the weeded zone.

Where native plants are regenerating among dense weeds, clear them some growing space but do not create large openings.

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Weed Removal Techniques

*Information sourced from Watiparinga Management Plan

Hand-pulling
Grubbing
Treading down
Cut-and-swab
Frilling
Recycling and Mulching
Follow-up and monitoring

Hand-pulling

Used for seedlings and young plants of any woody weeds such as olives, African daisy and Boneseed provided the soil is moist. Shallow rooted species will hand-pull when quite large.

Some plants that reproduce by more than seeds, need to be treated with great care and removed from the reserve in bags and destroyed. This applies to plants with numerous bulbils such as crow garlic or cormlets such as wild gladiolus and succulents which break into numerous vegetative parts, each potentially a new plant.

Wild gladiolus cormlets:

Removing olives around mature E. microcarpa. These seedlings grew from seeds dropped by birds roosting in the tree.

Removing boneseed by hand-pulling:



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Grubbing

Larger plants can be removed by use of grub-axes, mattocks or pelican hoes. Disturbance must be kept to a minimum. If sensitive plants are growing close to these plants it may be better to cut-and-swab to avoid disturbance both physical or sudden changes to microclimate.

Cutting down large multi-stemmed olive. This olive was isolated in an area where disturbance to surroundings was not a problem which meant it could be chopped down and the roots grubbed up.  

Cutting down and grubbing mature boneseed:

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Treading down

Disturbed soil, left after the removal of a weed, should be trodden down firmly to reduce the chance of leaving an open seedbed site available for re-infestation.

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Cut-and-swab

A form of chemical weed control that is less likely to affect neighbouring vegetation than spraying and is used extensively and effectively on many woody species such as ash and olive.

The offending plant is cut and an appropriate herbicide is swabbed onto the freshly cut surface. In most cases, if the stem is cut or broken and NOT treated, multiple stem regrowth results and the problem is compounded.
The treatment should be carried out when plants are actively growing preferably in late spring or summer and should not be carried out when rain is expected within 4 hours.

Relatively small single-stemmed plants can be cut with secateurs or a pruning saw near ground level and the butt liberally swabbed with the appropriate herbicide mixture. Large multi-stemmed trees such as olives require frilling.

Frilling

Frilling is used on large multi-stemmed trees such as olives. The stems are deeply slashed at an oblique angle particularly near the root stem junction and the cut surfaces are immediately swabbed with herbicide mixture using a flat paint brush.

Remove all twigs and sprouts from the base so that no green leaves remain. It is advisable to remove soil from the base of the trunk to about 2-5 cm below ground level and deeply slash the stem at that level. DO NOT allow cut surfaces to dry before poison is applied.

An olive poisoned by frilling.

Dead ash trees poisoned by frilling, next to young red gum:

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Recycling and mulching

It is important to recycle the nutrients in the cut off stems and boughs. Small woody stems can be left to rot down and form mulch. Large boughs are cur or sawn into smaller portions and spread over a wider area.


Selective placement of the mulch material is important. Be careful NOT to cover up regenerating indigenous species. Mulch can be strategically placed OVER unwanted herbaceous weeds, depriving them of light.

Mulching olive branches. Cuttings are left in areas clear of native plants and mulched using secateurs to increase the speed of breakdown.

Some plants that reproduce by more than seeds, need to be treated with great care and removed from the reserve in bags and destroyed. This applies to plants with numerous bulbils such as crow garlic or cormlets such as wild gladiolus and succulents which break into numerous vegetative parts, each potentially a new plant.

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Follow-up and monitoring:

Careful monitoring is on weeded sites is essential. Follow up hand pulling of emerging seedlings after adult weed is removed is essential to ensure re-infestation does not occur.

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Weeds and Fire

Article taken from Stop Bushland Weeds – A Guide to Successful Weeding in South Australia’s Bushland  by Meg Robertson and published by The Nature Conservation Society of South Australia 1994.

Native plant communities evolved with fires. Native plants regenerate from seeds released from fire resistant woody capsules, from seeds in the soil, or from resilient stems, roots, lignotubers or bulbs.

Regenerating Eucalyptus microcarpa (Click to enlarge)

Bushland weeds also have adaptations so they can persist in bushland. In bushland where a few weeds have been growing, large numbers of weed seedlings may appear after a fire. For example, a dense carpet of boneseed, broom or African daisy seedlings can smother emerging native plants.

Regenerating Blackberry

When a fire has gone through bushland, it is important to prevent weeds reaching maturity and adding to the weed seedbank. Weed seedlings should be removed by hand to assist native plants regenerating after fire. An extra effort at this time can prevent degradation and save work in the long run.

 

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Weeds Australia - National Weeds Strategy Weeds Australia Website

Strategies for specific weeds found in the park:

blackberry
Bridal Creeper
Bone Seed

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Last update: 3/05/2015