Safron thistles before and after.  After a wet year in 2019, many thistles grew from the extensive historic seed bank, once more covering the hillside.

 

          

Red Hill 1974 (Photo Chris Pavich)                            Red Hill 2012 (Photo Michael Mulvaney)

 

Resources:

• Canberra Invasive Plants Facebook Group
• ACT Invasive Plants Operations Plan 2020-25
• Invasive Plants – ACT Dept Environment, Planning and Sustainable Development
• ACT Naturalised Alien Plant Species Assessment (694 species listed)
• New South Wales Weed Control Handbook, Seventh Edition (nsw.gov.au)
• Invasive Plants Control Plan 2020-25 (arcgis.com)

Herbicides

The majority of weed removal on Red Hill is undertaken by either backpack/hand spray or by ‘cut and dab’. The most common herbicide used is Glyphosate (Roundup), which is diluted and a red vegetable dye is added.  Recently, the hazards associated with Glyphosate use have been highlighted globally, with a range of actions being reported in ‘Weeds News, including:

• Effects of sub-lethal doses of glyphosate on honeybee navigation
• Rounding up the risk of glyphosate
• Glyphosate fears see Roundup pulled at UK garden centres
• Glyphosate: A Chemical to Understand. Invasive Species Council, November 2020
• Sunshine Coast Council follows France’s lead in phasing out weedkiller

A report (Crit Rev Toxicol. 2016 Sep: 46 (sup 1):3-20) published in September 2016 titled “A review of the carcinogenic potential of glyphosate by four independent expert panels and comparison to the IARC assessment” concluded  that glyphosate is ‘unlikely to pose a carcinogenic risk to humans’. More…

Weed eradication on Red Hill

The main tasks which occupy the Red Hill Regenerators is removal of weeds from the critically endangered Yellow Box – Red Gum Grassy Woodland of the Red Hill Reserve.

• The ACT Government publishes weed maps of Red Hill showing the locations of major weed outbreaks (see Maps of Red Hill north and Red Hill south). The ACTG also publishes a Weeds Strategy.
• The ACT Government conducted significant weed eradication on Red Hill in 2013-14. The images show the weed densities in 2013-14 and the areas of weed eradication undertaken in 2013-14.
• Check out the “ACT and Southern Tablelands Weed Spotter“
• Download the ‘WeedWise’ App from the Apple App Store. This lists a massive range of weeds which are found in NSW and ACT and describes the recommended controls.
• ACT Parks & Conservation have provided a summary sheet showing recommended herbicide application rates for common weeds. More…
• NSW Dept Primary Industry Weeds Handbook 2014-15 here.
• The National Weeds Strategy Executive Committee with Sainty & Assoc has published the ‘WEEDeck’, a set of waterproof cards divided into six categories – herb, grass, shrub, tree, vine and water – for weed identification.

Cootamundra Wattle (Acacia Baileyana)

The annual debate over the practice of removing Cootamundra Wattles from Canberra Nature Reserves (including the Red Hill Reserve) has been ignited by a letter to the Canberra Times of 13 August 2015. More…

A response was published in the Canberra Times on 20 August 2015. More…

Cootamundra Wattle (Acacia baileyana) is a Class 4 Pest Plant in the ACT and is important to control due to its invasive nature.  It can be found on Red Hill in dense stands where it crowds out other local plants. The presence of Cootamundra Wattle in Yellow Box-Red Gum Grassy Woodland on Red Hill has been shown to promote a higher fire hazard in invaded sites compared with natural uninvited sites. More…

The Red Hill Regenerators remove dense stands of these plants by ‘cut and daub’ methods.  Where older plants are found we try to use the ‘frilling’ method which helps to retain bird nesting habitat.

More information can be obtained from the Molonglo Catchment Group.

The Cootamundra conundrum, by Jo Lynch (FoMM’s secretary, joanne.e.lynch@gmail.com) in Fronds, Friends of the Australian National Botanic Gardens Number 77 August 2014

Federal Government, Weeds in Australia, Acacia baileyana; on the page Description see Distribution and Impact (on woodlands…), on the page Management see Weed found (in all states and territories excl. NT),Weed declared (OLD, WA, ACT) and Weed control: … a long term strategy needed!

Invasive Plants and Animals Committee, Noxious Weed List, update Jan 2015: declared noxious weed in the ACT.

Greening Australia, Australian Native Plants for your backyard, see page 4, Environmental Weeds lists in particular Cootamundra wattle.

Queensland Government, Weeds of Australia, Fact Sheet Cootamundra Wattle, see Impact.

There are many examples of online sources of all states and territories that list Cootamundra wattle as Environmental Weed such as Weeds of Blue Mountains Bushland, Cootamundra wattle Bush Invader

ACT Government, Are your garden plants going bush

Here is a leaflet produced by the Regenerators about Cootamundra Wattle which can be downloaded here…

In summary:

• ACT Woodlands and forests have a large range of natives which are beautiful and provide habitat to native wildlife such as the local Silverwattle that flowers early spring ie the same time as CW (therefore hybridises with the CW);
• CW is a declared weed in the ACT because of it is highly invasive and impacts on local species and threatened ecological communities. It is also declared in other states and considered a bush invader of great concern by all Australian states and territories except NT where so far it is not found;
• CW does not require fire to germinate. When old CW die and light penetrates to the ground seeds stored in the soil germinate and form thickets, the canopy of which prohibits growth of other plants;
• A long term strategy is required to remove CW that have already changed the character of YBRG grassy woodland which is listed critically endangered.
• The removal of CW would benefit local plant species and wildlife depending on those.

 

Some of the more common weeds found on Red Hill are pictured below:

Here is a picture of Chilean Needle Grass (a weed of national significance), which can be sprayed in winter when it can be more easily seen.

 

More about Patterson’s Curse

 

More about Verbascum

 

 

More about  Blackberry

 It is important to distinguish between the blackberry (a weed of national significance)

and the native small-leaved bramble, which provides valuable nesting habitat

 

More about Sweet Briar Rose

 

More about Pyracantha

More about European Nettle Tree

More about Tree of Heaven

More about Oregon Grape

More about St John’s Wort

More about the Greater St John’s Wort beetle

 

 

Scotch thistles are usually found under old eucalyptus trees where cattle have historically sheltered. The simplest treatment is to chip them out before they get as large as this one, or spray at rosette stage. Once they are in flower they will set seed (see above) even if chipped.