Broadleaf weed control

How selective weedkillers work

Lawn weedkillers for broadleaf weeds are taken up through the leaves of plants like dandelion, clover, plantain and daisy, and disrupt their growth. Grasses are largely unaffected at the label rate. They do not stop new weed seed germinating, and they do not touch weedy grasses such as crabgrass.

When

Mid-April to the end of May, when weeds are growing actively and the leaves are big enough to absorb the product. Pick a calm, dry day with no rain forecast for at least six hours, when the air is mild rather than very hot.

How

• Use a selective broadleaf herbicide authorized for lawns in your country, and follow the label exactly.
• Spot-treat individual weeds or patches rather than spraying the whole lawn when there are only a few.
• Do not mow for a few days before and after, so there is plenty of leaf to absorb it.
• Keep it off newly sown grass; most products need the lawn to have been mown several times first.
• Do not put the first clippings after treatment on the compost heap; check the label.

The alternative

A handful of dandelions is quickly dealt with by a weeding tool that lifts the whole root. Long term, a thick lawn is the real cure.