Saturday, 3 January 2015

Weed better talk about this issue...

 Believe me, for most of my life I thought weed was either something you smoked or kicked sand in the face of. If you’d told me years ago that I would develop a malevolent dislike for the plural of weed, I would have thought you were off your trolley, barmy, nuts, crazy, absolutely stark raving, stonking mad. But then I suppose I went “troppo”, ended up living in the suburbs of Sydney, and discovered the awful harm these pernicious things actually did.  To be fair, I was raised in the English Midlands where weeds were harmlessly insignificant and there was so little genuine nature left, that they were almost as good as it got.  I’ve since learned that around 80% of Britain’s flora is not endemic. 
 
 Fast forward to life in the burgeoning metropolis of Sydney, which is still blessed to have pockets of native vegetation interspersed with suburbia. Here you’ll find incredible plant biodiversity and species that have survived from the time of the Gondwana super-continent, learning to adapt and evolve to dry, hot, arid conditions and nutrient poor soils and fire. You’ll also find lots and lots of weeds. These are not weedy weeds though...they’re aggressive super-sized marauders on a testosterone fueled rampage.  And yes, like just about everything else that’s bad in this wonderful continent...the ignorant, thoughtless, careless colonialists and their progeny are to blame.


 It all started with the first British settlers wanting to plant reminders of “home” at every given opportunity and it continues to this day with the horticultural industry still bringing in new profit-making varieties from overseas. Every single one is a potential weed.

Weed management  actually costs the Australian economy around $4 billion annually,  weeds represent, the second greatest threat to biodiversity after land clearing and almost half of Australia's 220 declared noxious weeds were introduced deliberately, one third of these as garden ornamentals.  

  People still prefer to plant “exotics” rather than their own native species and chances are these will invade the bushland and outgrow, overwhelm and displace the flora that was there originally, especially when boosted by the steroid effect of high nutrients provided by garden fertilizers and urban run-off.  If you love nature, it is pretty hard to witness the demise of high diversity bushland as it gets swamped, smothered and eventually killed off by a suite of foreign invaders. These are some of the most prominent rogue species on Sydney’s Northern Beaches. If they exist in your garden, please get rid!

Asparagus Fern.  This menace is from South Africa and like many other weeds..its seeds are spread by birds that eat the red berries.  You can offer see this as a feature plant in suburban gardens, especially in hanging baskets.

Lantana. This native of Central and South America was brought to Australia in around 1840 as a garden ornamental. It has now invaded around 4 million hectares and graziers spend over 17 million dollars per annum trying to control it.  (NB in heavily denuded areas it is often the last refuge for small birds so caution is advised before hurried removal). Lantana has been cultivated for well over 300 years and has hundreds of hybrids. It has been nominated as among the top hundred world’s worst invaders. It is thought that the original un-hybridised version no longer exists in nature.
Cotoneaster. This is another weed from China which is highly invasive.  It is a common garden plant which escapes into the bush and also acts as a food source for feral bird species.
Senna/Cassia  This is another nasty piece of work from South America which was imported here as a garden plant..It is very invasive and thrives in all conditions.
 
Morning Glory This is another ostensibly “pretty” garden plant but once it gets into the bush it can be a nightmare to remove. A native of China, it was used for medicinal purposes due to the laxative properties of its seeds.
Ochna is a native of South Africa with bright yellow flowers. It is also known as the Mickey Mouse Bush due to the plant’s red sepals and black seed which has a passing resemblance to the Disney character. Another rampant invader of our bushland.

Privet. As a child in Birmingham UK, we had massive privet hedges in our garden which were sculpted and lovingly preened. Little did I know that in later years I would be frantically cutting these plants down. In Australia, their black fruits are greedily consumed by birds which collaborate in spreading this pest deep into fragile bushland where it grows rampantly. There are small-leaf and broad-leaf varieties native to Eastern Asia and European privet which is native to Southern Europe and Northern Africa.
Pittosporum Undulatum (Sweet Pittosporum). This is a weird one as it is actually a native plant that has gone feral and is now out-competing other species and shading them out. It has done especially well in soils that have been modified by humans and takes advantage of high nutrient levels.

For help identifying weeds of the Sydney region click here  weed I.D.