Chilean rhubarb in the gun

Chilean rhubarb is an unusual plant that has been quite popular with gardeners.
It thrives in damp places such as alongside ponds and streams and has a dramatic appearance.
It has large, spiny stems that are up to two metres tall in a favourable location. These are crowned with enormous umbrella-like leaves, often a metre in diameter.
The leaves are rough, lobed and hairy and hence unpalatable to stock. Several long flower stems arise from the centre of the plant in spring.
Each stem is covered with small flowers that eventually produce thousands of tiny seeds. The leaves blacken and die in the winter but the crown happily survives frosts to re-grow the following spring.
As its name suggests, it is a native of the Chilean and Argentine Andes but it is very adaptable and has naturalised in many parts of the world.
It has become a serious problem in parts of Ireland where it smothers native vegetation.
Closer to home, it has infested many kilometres of coastal cliffs in Taranaki, surviving gales and salt spray. Helicopters and abseillers have been employed in the battle to control it.
Within our region it has been found growing in the wild not far from a pond with mature plants in rural Katikati area.
If you do have such a plant adorning your pond or a damp shady place it would be wise to remove it. If you see it in the wild, let the Bay of Plenty Regional Council know.
Gunnera tinctoria is listed in the National Pest Plant Accord and is therefore banned from sale, propagation or distribution.
However we have found it mislabeled as Gunnera manicata and available for sale - please resist the temptation to buy!
Chilean rhubarb can be controlled by digging out, chopping up the central stem finely and composting all vegetative parts. Any seed heads should be put in land fill rubbish.
In spring, cut off the leaves and paint the stalk stumps with glyphosate (eg Round-up) at 250ml per litre. Over spray large areas in spring or summer when actively growing with glyphosate at 100ml per 10 litres water.
For more information on this and other pest plants visit weedbusters website www.weedbusters.co.nz or contact Bay of Plenty Regional Council Pest Plant Officer Sara Brill for advice on 0800 ENV BOP (368 287) extn 8503.