WEED OF THE MONTH WITH GINA WILLIAMS, DOC
Giant reed Arundo donax
Giant reed just loves the Northland climate and this tall, leafy, bamboo-like grass is a noticeable menace along roadsides and riverbanks.
Giant reed's hollow stems grow to about 4cm wide and 5m high, with alternately arranged leaves clasping the stem.
The moststriking features of the plant are the mammoth clump sizes, the tall stems and plume-shaped flower heads, which are now visible.
Seeding is rare in New Zealand but rhizomes spread readily down waterways and from garden dumping. New plants can grow from stems and root or rhizome fragments.
Originating from the Mediterranean, giant reed has developed a weedy reputation in many countries. It is known to invade forests, streams, intertidal areas, roadsides, farms and more. It poses a flood and fire hazard and blocks ecological processes in native sites. Giant reed is listed in the Northland Regional Council's Regional Pest Management Strategy as a containment plant causing, or having the potential to cause, adverse impacts on Northland's environmental, economic, cultural and recreational values. It is banned from sale and distribution.
A recent Weedbusters Picnic in Parihaka Forest in Whangarei addressed several clumps of giant reed canes growing along the Hatea river forest walkway.
Community Weedbusters, Northland Conservation Board, Department of Conservation, Northland Regional Council and Whangarei District Council weeds contractor participants cut the reed stems and applied herbicide to the stumps.
Weedbusters also found seedlings of taiwan cherry, monkey apple, chinese privet and wandering willy spreading from neighbouring gardens.
If you want information about how to audit your garden for weeds, contact Gina at DoC or go to www.weedbusters.org.nz for more information. A Plant Me Instead booklet is also being compiled, full of the top-voted weedy plants and non-weedy alternatives for your garden.
To place your vote for worst weed, email gwilliams@doc.govt.nz or call (09) 470 3331 for an entry form. All those who vote this month and in December will receive a copy of Plant Me Instead.
