War on Weeds in ongoing

from The Fringe, April 2020

Bandstanding: Wendy Morris

Following last months’ annual War on Weeds, weed bins will still be available over the next few months, reports FIONA DRUMMOND. This is welcome news as weeds will be easier to dig out once the autumn rains arrive.

Removing weeds is one way of dealing with the weed issue, but preventative measures to minimise the spread of weeds are also important.

Take kahili ginger for example. Despite its alluring heady fragrance, wild ginger forms dense clumps in native forests, smothering young plants and preventing native seedlings from becoming established. This makes it a serious threat to native ecosystems. It typically has around 100 seeds per flower head, and these are often spread by birds. When dealing with a large area of ginger, start by removing the flower heads and burning the seed heads. This won’t kill the plant but will stop it from seeding that year. Then you can concentrate on spraying or removing the whole plant.

Small seedlings can be hand-pulled and disposed of carefully. Small clumps can be dug out, as long as all of the root system is removed and disposed of safely. Rhizomes (the fleshy roots) can be placed in a black plastic bag and rotted, or placed in a weak herbicide mix, crushed, dried then burned. Larger clumps can be sprayed using Escort or Vigilant. It is best to cut the stems down to the rhizome first, and then drill several holes in the rhizome before adding the herbicide. This will make the control more effective.

I am more tolerant of agapanthus even though it also can prevent other seedlings from growing. Nothing beats it as a hardy and stunning summer flowerer, synonymous with a Kiwi summer. It can easily be kept in check by dead-heading when it finishes flowering so the seeds don’t get a chance to germinate elsewhere. Unlike ginger, the seeds are not dispersed by birds, but by wind and water, and each flower head can have between 650 to 4000 seeds. This makes removing the spent flowers essential to keep the plant contained. I recently wrote to Biosecurity with our concerns about this plant and received a response from the project coordinator of Environmental Services thanking me for bringing it to council attention and assuring us that a recommendation will be made to add it to the Regional Pest Management Strategy. Council do appreciate public concern and reports to do with pest species.

If you are keen to find out more about pest plants, Auckland Council Biosecurity have an A-Z listing of all plants including the control measures for each. They are also planning a Pest Plants Environmental Talk on Thursday April 2, 6-7pm at Te Atatu Library. Visit http://www.communitywaitakere. org.nz/index.cfm/news-events/pest-plants-freeenvironmental-talk/.

Temporary bins will be available on specific dates at the following West Auckland locations: • Waiatarua Community Hall, (911 West Coast Road) May 2 – 3. • 69 Victory Road, Laingholm: May 2 – 3. • 15-17 Mountain Road: April 4 – 5 and June 6 – 7. • Kōwhai Reserve (28 Withers Road): April 4 – 5 and June 6 – 7. There are also two permanent weed bins, at Piha Domain (Seaview Road) and Huia Domain (Huia Road)

It is important to respect these bins – they’re for invasive weeds only. When illegal dumping happens, Council has to pay for the rubbish to be removed, making the service more expensive and less viable.

The bins should not be used for bamboo, large branches or tree trunks, palm trees, cabbage trees, general garden waste and weeds from near kauri trees (to prevent the spread of kauri dieback disease). Agapanthus have hundreds of seeds per flower head, so deadheading is essential to avoid spread.

Other pest plants are not so well known. On Exhibition Drive we have been attempting to eliminate a weed plant that doesn’t feature highly in Auckland Council’s list of pest plants. However, it does have the potential to be a very invasive plant. Bidens frondosa or Devil’s Beggarticks is a North American species of flowering plant in the sunflower family, and an invasive weed in Canada. It has a leaf resembling the cannabis plant but, as its common name suggests, the flowers have ticks or burrs attached which will stick to clothing or dogs, and as such can be easily spread. It is essential to remove this plant before it seeds. Bidens Frondosa or Devil’s Beggarticks on Exhibition Drive