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WELCOME TO THE AWHITU PENINSULA:
Towards a Pest-Free Peninsula: Plant Pests
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Towards a Pest-Free Peninsula: Plant Pests
The Awhitu Peninsula Landcare group has, since its beginnings in 1994, been involved in identifying and advising on control methods for weeds. From late 2004 till early 2008 we ran a very successful coordinated pest control project, supported financially by the Department of Conservation. We have had on-going cooperation and substantial assistance from the Auckland Regional Council, particularly the local Biosecurity Officer. In choosing which plant pests to describe, we have ignored common annual garden and pasture weeds which often have positive uses, and which most gardeners and farmers know how to manage. Our concern here is invasive weeds which threaten the biodiversity of the Peninsula, or which may cause problems for animal or human health. We hope all newcomers, as well as present residents, will join our ongoing campaign against pests, and help to create new ways of making the environment healthier, more productive and sustainable for everyone on the Awhitu Peninsula.
1. Climbing asparagus (Asparagus spp.)
Climbing asparagus (sometimes called the Old Man's Beard of the north) is a particular problem on the Peninsula because it forms a dense ground cover in shady areas, preventing forest regrowth, and also spirals up existing plants, suffocating them. It spreads as a creeper by taking root at nodules, by underground corms, and by orange berries which birds love. If you see small plants, you can dig them out. But any corms left in the ground will re-sprout, and you will probably need to spray with a systemic herbicide.
This woolly-leafed shrub is from the same family as many food plants (potatoes, tomato, eggplant) but has a mild toxic effect. It can also cause skin irritation in some people. It forms dense stands that inhibit native regrowth, and also invades pasture. Small plants should be pulled out as soon as you see them. Larger plants should be cut just above ground level, and the stumps have a herbicide applied. 3. Pampas (Cortaderia spp.) and purple pampas - sometimes confused with the useful native toetoe
With leaves like canna lily, and a large yellow flower with a beautiful perfume, kahili ginger (H. gardnerianum) and yellow ginger (H. flavescens) are handsome plants. However, they have large, branching tuberous roots that form dense mats up to a metre thick, and form big colonies in native bush, totally preventing native shrubs and trees from growing. They spread by root and by seeds, and should be exterminated wherever they are found, using appropriate systemic herbicides. 5. Ragwort (Senecio jacobaea)
6. Gorse (Ulex europaeus)
However, unlike the plants mentioned above, gorse can also have some uses during the process of revegetating an area with native bush. On crumbly slopes it holds soil and prevents erosion, and it fixes nitrogen in the soil. It can act as a barrier against possums and grazing animals. Bees make good honey from its flowers, and its timber can be used for furniture, woodturning and firewood. Because it only grows in sunny places, it will eventually be shaded out by native bush. But in pasture, near neighbours, on road edges, or if it is too large and overshadows natives, it can be a major problem. It spreads and grows rapidly from seeds, and the seeds can last in the ground for 50 years or more. Planting fast-growing exotics such as pines or cypresses into lines cut through gorse is one way of dealing with it. Grubbing followed by hard grazing (especially by goats - although we don't advise herds of goats on this sand country!) is another. But spraying with an appropriate herbicide is the most effective method of control.
There are a number of popular garden plants that escape and cause problems, for example:
We welcome newcomers to join us in
protecting our past…planning our presence…feeding our future |
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