Header Image

Helping grow
the country

< Back to Blog
1 November 2019 Matthew Crampton

Weed control in new pastures

New pastures are a great opportunity to lift production and fine tune the production dynamics on your farm.

After sowing your new pasture paddocks, ensure you monitor them as they emerge. Once the clovers are at the two trifoliate stage, it is a good time to assess the weed pressure. Some paddocks can be clean during establishment but many have a resident weed population that emerges at the same time as sowing down the new pasture. Checking the paddock at this early stage allows selection from a range of herbicides that can prevent the weeds competing for nutrient, moisture and light.

Weeds are much easier to control when they are small, so once your clovers have got two trifoliate leaves, check the paddock for weeds. Identifying the weeds at this early stage can be tricky but I  recommend a copy of “A Guide to the Identification of New Zealand Common Weeds in Colour” by E. A. Upritchard. This little red book is a good investment to have in the truck, and shows the most common weeds at the seedling stages. Identification of weeds is required so the correct herbicide can be selected.

A couple of common weeds seen in new pasture are shepherd’s purse and spurrey/yara. Both these weeds have distinctive characteristics. The shepherd’s purse seedlings have distinctive white hair on their leaves in a cross shape, these can be seen with a hand lens. Spurrey/Yara is an interesting weed, the seedling has upright, round leaves which can be mistaken for grass, but it has a distinctive pattern of four upright leaves originating from the stem above ground level. As with many weeds, spending time to get to know them helps with identification. I suggest if you would like some help identifying weeds, contact your local PGG Wrightson Technical Field Representative.

Weeds in pasture often show up where the gaps are. If you have used weed control and left open areas, use some more seed to fill in those gaps and prevent the weeds establishing. This can sometimes happen, even in new pastures where something has gone wrong during establishment.

If your new pastures are patchy with large gaps, consider using the drill to fill in those gaps because weeds do not provide much in the way of value feed for your stock compared to modern productive grass species. Contact your local PGG Wrightson Technical Field Representative who can help.

Matthew Crampton

Share this page