Declaring war on weeds

Over the last couple of weeks I’ve finally been able to get a start on the gardens here at the Cottage. What a sorry state they are in! The soil’s horribly compacted and woefully lacking in organic matter (with the exception of last year’s potato bed and a spot where mint had gone feral) and decidedly lacking in worms. There are a few of the lovely crawly things about though, and I noticed lots of tiny little wormlings when I gave the compost a good a stir on Sunday.

Aside from planting out a few potted herbs that desperately needed proper dirt and transplanting some self-sown seedlings I’ve discovered about the place, my gardening activities have largely focussed on weeding. Not your usual keeping-the-garden-beds-clear type work, but serious weeding on the slash-and-burn scale. You see, like many older rental properties my garden is home to grand collection of well established declared and noxious weeds.


My place is less cottage-garden and more weed-topia at present…

What is a declared weed? One that’s listed under relevant legislation banning it from sale and requiring active management to control it’s spread. Here in Tassie it’s the Weed Management Act 1999, and legislation decrees that:

(a) A person must not import, or allow to be imported, into the State any declared weed except with the written approval of the Secretary.
(b) The tolerance level for declared weed seed in imported grain will be 0 seeds per kilogram.
(c) Landowners and managers must take all reasonable measures to control the impact and spread of a declared weed.
(d) A person must not propagate, trade or otherwise distribute declared weeds or anything carrying declared weeds except –
I. transport for purposes of disposal and
II. sale or transport for purposes other than disposal where authorised by the Secretary.
(e) A declared weed must be disposed of in a manner which will not result in further infestation.
(f) A declared weed must be eradicated from areas of the State where this is considered feasible.

(emphasis is mine)

So far I’ve found 4 weed species in my garden that are listed as declared or of concern in Tasmania: fennel (Foeniculum vulgare), mirror bush (Coprosma repens), English ivy (Hedera helix) and cottoneaster (Cottoneaster sp.). It’s going to take a lot of hard work, but I’m determined to do my best to get rid of them. The mirror bush is fairly easy: cut it down and paint with poison (likely many times over). The ivy and fennel present more of a problem as they’ll keep coming up from runners and seeds. The cottoneaster I’m afraid I’m going to have to live with, as it’s a 5 m tall tree and felling that is going a little too far as a renter!

It is worth remembering that I rent, when I’m out there labouring away in the garden. Sometimes I think I’m a little insane putting so much hard work into someone else’s garden with no long-term reward. After all, there are reasons weeds are so common on rental properties: they’re hardy, almost impossible to kill and will survive even the most neglectful and brown-thumbed of tenants. When I feel like giving up, though, I remember the impact of weeds on the environment.

Weeds take over, choking both native vegetation and agricultural land. They reduce the habitat available for native animals and often provide a competitive advantage for feral animals. They change the structure and function of an ecosystem, altering soil structure and chemistry, water flows, food chains and biodiversity. Some are poisonous to native animals and livestock: introduced onion weed is causing a horrible liver disease that is killing wombats in the Riverlands. The Australian Government estimates the cost of weeds to agriculture alone at $4 billion per year (cost of control plus lost production). Weeds are bad news!


…though the mirror bush has met my friend the pruning saw.

My first proper job as an ecologist was monitoring the condition of creeks and rivers around Brisbane. It was a frank and depressing education in just how bad weeds can be, with waterway after waterway choked with introduced weeds, the native bank-side vegetation replaced with garden escapes and other ferals. Stopping the spread of weeds matters, and to do that we need to do our best to eliminate sources of seeds and runners. That means:

  • Getting informed about what are the problem weeds in your area (your local Council is a good place to start)
  • Cutting down and pulling out weeds where possible
  • Trimming weed flowers and fruits before they set seed
  • Disposing of garden waste properly, instead of dumping it in the bush or other places where seeds can spread

For me, it means I’m going to spend many more hours out in the garden, wrangling the weeds and fighting the never-ending battle against the invaders. I hope you will join me.

2 Comments on “Declaring war on weeds

  1. A book I read last year has shifted my thinking about exotic and invasive plants: Rambunctious Garden by Emma Marris. We still need to protect biodiversity and encourage native species (and backyards may be one of the most effective places to do so), but she suggests it may be counterproductive to expend so much energy eliminating species that adapt well to the environment. She travelled extensively for her research. It’s an informative and entertaining read even if you disagree with her conclusions.

    • Thanks for the link to Emma’s site. Her book looks very interesting and I do tend to agree: some feral plants and animals are here to stay and we do need to work out how best to live with them and help our native flora and fauna adapt. Australian author Tim Low argues something similar in The New Nature”, which I’ve been meaning to read for many years.

      That said, I will keep removing declared noxious weeds from my garden, else I’ll soon have no productive space left (though at least I can eat the invasive feral fennel).

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