December 9, 2010
Temuka pond plant poses potential problem
Keen gardeners who might be tempted to bring home an unusual and attractive aquatic plant that thrives near Temuka are
being warned by Environment Canterbury about its invasive potential.
Many years ago an oxbow lake (a river meander, now cut off from the main flow) was created in the Temuka River when the
river changed course. At some point it became colonized by cape pondweed (Aponogeton distachyus), also known as water hawthorn, and today almost the entire pond surface is covered with this plant, which is currently
The small oxbow lake is situated behind the Temuka golf course on land between the river and the stopbank, which is
managed by Environment Canterbury.
“This berm area is a great place for a walk on summer evenings,” says Environment Canterbury’s rivers’ engineering
officer Bruce Scarlett. “We like to see people making the most of it as a recreational area but just want to warn them
that cape pondweed is on the Ministry of Agriculture and Forestry’s “watch” list, as an emerging pest plant, with the
potential to spread.”
Cape pondweed has clusters of small white fragrant flowers which bloom on long stalks above elongated oval leaves. In
some parts of New Zealand cape pondweed is considered a pest plant because of its ability to form large floating mats
which can create a flood hazard.
Bruce Scarlett is interested to know if anyone in the Temuka area knows the history of how the cape pondweed got there,
as it is not widespread in the rest of the region. Anyone with any information should speak to Bruce directly or leave a
message at Environment Canterbury’s Timaru office - 03 687 7800.