Whanganui Midweek: Watch your weeds!

Moth plant (Araujia hortorum) has pods that open up to spread windborne seeds. Photo / Horizons Regional Council

Watch your weeds!
By Lyneke Onderwater
Whanganui is a weedy town and that is due to our lovely mild climate. Once every few years I get to do a very short-term contract with Horizons Regional Council: spotting weeds. Not just any weeds; these are weeds that are not rampant here, but would be if we didn't control them. I get a list of weeds and locations and look for them. You may see me biking around with an orange Weedbusters high-viz jacket on. The weeds on this year's list are: woolly nightshade, moth plant, blue passionflower, cathedral bells, climbing spindleberry, Chilean rhubarb, Queensland poplar and boneseed.

Woolly nightshade (Solanum mauritianum) is the most common of this list, but Horizons is planning an awareness campaign soon, so I won't go into detail about that one.

Boneseed (Chrysanthemoides monilifera) is a common pest in Whanganui. Photo / Horizons Regional Council

The next most common (especially east of our awa) is boneseed (Chrysanthemoides monilifera). In Whanganui it is an early, yellow-flowering shrub, which unfortunately has done its flowering for the year and is currently hard to spot. One of the identifying features of young plants is the woolliness of young stems and, easier to spot, the newest leaves. The leaves look similar to those of dimorphotheca (Osteospermum fruticosum), but the flowers and growth-form are very different.

Blue passionflower (Passiflora caerulea) was thought to be in only a few places when I started with Horizons, but many new locations have been found, especially in Gonville. It is a relative of the commercial variety and the banana passionfruit, also a weed. Although the flowers of this weed are very similar to the commercial one, the leaves are very different: dark green and consisting of up to five lobes (or "fingers").

Moth plant (Araujia hortorum) is a vine that continues to pop up despite control of some significant infestations. It has little white flowers that turn into choko-like pods. These open up when dry to spread windborne seeds. Characteristic also is the smelly, milky sap that comes out when the stem, leaves or roots are broken.

Chilean rhubarb (Gunnera tinctoria) looks similar to the edible rhubarb, but has huge prickly leaves that grow up to 2.5m high and die down in winter. It likes moist places, often growing on the edges of ponds or swampy places. It flowers around now and these come on spikes about 1m tall.

Queensland poplar (Homalanthus populifolius) is a shrub with poplar-like, almost heart-shaped leaves that often have a reddish colour especially in the colder season. Flowers are creamy and come on droopy spikes. There is a similar native species, the Kermadec poplar (Homalanthus polyandrous), which can be grown in frost-free spots.

Cathedral bells (Cobaea scandens) is an invasive vine with stunning purple flowers and climbing spindleberry (Celastrus orbiculatus) a deciduous vine that turns golden in autumn. They appear to be almost exterminated in Whanganui, but it pays to be vigilant.
Www.nzpcn.org.nz and www.weedbusters.org.nz are the best websites to find more photos and information.

If you think you have any of these plants on your property or know of any other locations please get in touch with Horizons on 0508 800 800 or report it in the snapsendsolve app, available at www.snapsendsolve.com.

There are many other weeds in Whanganui, not targeted in this survey, that need attention. Climbers especially cause problems and sometimes even the collapse of huge trees. The following are rampant and need control: ivy, old man's beard, banana passionfruit, Japanese honeysuckle, blue morning glory, non-native jasmine (Jasminum polyanthum) etc. The list is too long to mention them all, but check the Weedbusters website above, where you can also download the Plant Me Instead booklet for our area, which is a good start. This website also lists ways of dealing with the troublemakers. Note that these weeds should not be reported to Horizons as it is not in their remit to control them. The onus, in these cases, is on the property owner.

Lyneke has been a weed spotter since the turn of the century. She has to go overseas to NOT see weeds.