Nobody wants weeds in their garden, but knowing exactly when to unleash herbicidal fury upon the pesky intruders can be tricky. Here, a gardening expert shares some great advice to keep on top of the age-old problemNobody wants weeds in their garden, but knowing exactly when to unleash herbicidal fury upon the pesky intruders can be tricky. Here, a gardening expert shares some great advice to keep on top of the age-old problem