The importance of grass and weed control
We always stress that newly planted trees and hedges need a 1 metre radius clear of grass and weed for at least 3 years after planting. But you often see trees growing with grass around the base – so why not just let it grow around your new tree?
Just like your newly planted tree, grass and weeds are thirsty – the mat-forming roots of grass especially can intercept a lot of rainfall before it soaks into the soil below. So, to give your tree the best chance of survival, getting rid of the competition is vital! By about three years after planting, the tree roots should have spread far enough to allow the tree to access water and nutrients from far and wide, so other plants near the base are less of an issue.
A word of warning: mowing and strimming around the base of the tree in the crucial early years is not the solution. Cutting grass just makes it grow back more vigorously! Plus, it leaves the pesky roots intact to gobble up water and nutrients that your tree would dearly like to get into its own roots. Even worse, strimming invariably leads to lacerated trunks, which can be the death knell for the poor tree. Please don’t strim close to trees!
Chemical weed control is an effective way to clear the ground in a planting site. However, avoid spraying near trees and hedges in the growing season as any spray that drifts onto leaves will cause these to go brown (and potentially harm the tree/shrub). It’s a little trickier around evergreen shrubs. The alternative is hand-weeding – which is quite manageable for a handful of trees but a more of a daunting task over a large area, and can leave unwanted roots and seeds to grow back.
Pegging a mulch matt around the base of trees and topping this with a thick layer of mulch will go a long way towards stopping weeds. Couple this with chemical control at the start and you may find you don’t need to do any more spraying or weeding over the crucial three-year establishment period.