The work
What’s involved
Weed control in grassland is usually done one of three ways: a boom sprayer across the whole field where weeds are widespread; spot spraying with a knapsack or hand lance where they are scattered; or a weed wiper, which wipes herbicide onto tall weeds such as thistles and rushes and misses the shorter grass below.
Most grassland herbicides target broad-leaved plants and leave grass alive, but they will also kill clover and wildflowers. Tell the contractor if you want to keep clover or have areas that should not be sprayed.
Ragwort is often pulled or dug by hand, especially on small areas or where spraying is not suitable. Every plant, root and all, has to be bagged and taken away – pulled ragwort left lying in the field is more dangerous to horses than the living plant.
Every product label sets a period during which animals must be kept off the treated area, and many say to keep stock off until poisonous weeds such as ragwort have died and disappeared. Ask the contractor which product they will use and what that period is before you book.
When to do it
Most grassland weeds are best sprayed when they are actively growing and at the rosette or leafy stage, before they flower: typically spring for buttercups and ragwort rosettes, and spring or early autumn for docks and thistles. Spraying weeds that have already flowered or been topped recently gives poor results, because there is too little leaf to take up the chemical.
Spraying needs a dry, still day with no rain forecast for several hours. Wind causes drift onto hedges, gardens and watercourses, and rain soon after can wash the product off.