Pasture Watch
Cudweeds to watch for
Why are they weeds?
Fast growing, competitive
Where are they found?
Nationwide, mostly in lower rainfall areas
Are they toxic?
No
Other attributes
Flowers are a food source for some species of butterfly caterpillar
I RECEIVE phone calls a couple of times a year from colleagues and farmers about cudweeds. They're usually growing in crops such as asparagus, in lawns, on waste ground, or areas of thinning or damaged pasture.
'Cudweeds' are several different plants that look similar, and were traditionally used as feed for cows that had stopped chewing their cud.
A couple found in NZ are thought to be native, but most are from North or South America. The ones you're most likely to see are:
• purple cudweed (Gamochaeta coarctata);
• Japanese cudweed (Euchiton sphaericus);
• Jersey cudweed (Pseudognaphalium luteoalbum).
Cudweeds can be annual, biennual or short-lived perennials. The leaves and seed heads are covered in distinct, fine, white ‘woolly' fibres. Some are hairy on the undersides of the leaves, others have it on both sides.
They overwinter as small rosettes, their wide leaves preventing other, more useful seeds (such as ryegrass) from germinating. They also sit flat, avoiding mower blades.
In spring, they grow an upright stem which forms a flowerhead, then tiny seeds.
There are several cudweed varieties, but they all look similar, with hairy leaves and upright stems in spring.
How to control cudweeds
The best way to keep cudweeds out of pasture is good grazing management. Densely grassed, well-fertilised pastures are much less likely to be invaded.
Don't let stock chew pasture to a low level in autumn. Longer pasture helps to prevent cudweeds from establishing.
If you have cudweed in your lawn, mowing doesn't help much, so you may need to hand-pull small infestations or spray it. Options include glyphosate or glufosinate-ammonium.