Pasture Weed Watch
How to control groundsel
SPRING is a good time to eradicate groundsel from your block.
It's a small, upright weed that won't compete with your pasture for water, light and nutrients, but it can be a problem (see below, right).
You're most likely to see it in disturbed soil in paddocks and garden beds.
One of its other names is old-man-in-the-spring. I can't find an official background to this interesting name, but I'd surmise it may be due to groundsel's extremely fast lifecycle, just 5-6 weeks from germination to seeding.
This speedy growth means it can quickly establish itself, efficiently spreading its seeds in flower gardens and disturbed areas of soil used for cropping and horticulture.
Groundsel can grow to half a metre high. In direct sunlight its leaves often look shiny. As the seed head develops, it sprouts cylindrical-shaped yellow flowers, approximately 10mm in size.
Groundsel has been linked to a fungus which is renowned for causing black root rot in legume plants such as lucerne, peas and red clover. It is also a host for the magpie moth ( Nyctemera annulata) which is endemic to New Zealand. The moth feeds on the underside of the groundsel leaves, or any species of the other 39 members of the Senecio family.
How to control it
Controlling groundsel in your garden or lawn can be as easy as pulling it out by hand. A thick layer of mulch will stop any seeds germinating.
Control options in pasture include herbicides such as Pasturekleen Xtra, a 24D broadleaf spray.
Early spring to autumn is the time to act. Ideally, graze the area and then leave it for a week to allow for weeds to freshen before spraying for best results.
Always follow the spraying instructions on the label of the product you have purchased. Use on actively growing plants to ensure successful control.