A lot of gardening web site tell you that you need to improve all your garden soil before you start planting.
Well in the case of shrubs I take a different approach, which has worked well for me.
The ground of a typical site following the build is in pretty poor condition.
Little top soil so even the weeds are struggling to survive.
A week before planting I look to kill all the weeds using a weedkiller containing Glyphosate. (If you want a non chemical solution I would suggest using a steam gun) You are aiming to kill the roots , not just the foliage.
I normally follow up with a second weedkiller the day before planting.
Rather than improve the whole area and give potential weeds a break I concentrate on the area where the weeds will spread over the next 2-3 years.
I dig a hole around 3-4 times the diameter of the shrubs pot and around 100mm deeper and place the plant on a bed of compost in the hole.
I then backfill around the rootball with a mixture of 50% compost and 50% material excavated from the hole.
If you have got a worm farm it’s a good idea to include a couple of trowels of that material, with a few of the worms.
Make sure the backfill is firm so the plant doesn’t move around.
Rather than buy expensive wed mat I simply use a layer of newspaper, typically at least 3 sheets thick with generous overlaps.
I then cover the paper with a mulch, either gravel, or bark as in the photo.
If you are doing a big garden don’t buy your mulch by the bag, it’s cheaper to buy it by the cubic metre from a garden supplier.