If you want to beat the weeds and reduce weeding to the absolute minimum, a good idea is to lay a weed suppressing membrane. Garden centres sell weed suppressing membrane which are tough woven plastic sheeting. The images below show a border which has a weed suppressing membrane laid on top of the soil, and then covered with a mulch of bark. A membrane can be laid at any stage but it's significantly easier to do this when the border is new, or if you are re vamping it and removing most of the plants and shrubs so the border is clear.
The thick membrane and a layer of bark effectively stop most weeds. If you move into a house with a new garden or are laying out a new border, this is an ideal opportunity to cover the border with horticultural membrane and with bark to reduce garden weeding.
When the border is prepared lay the membrane and to conceal it, as its far from attractive, cover with a layer of bark chippings /topsoil. When you plant, using a sharp Stanley knife or scissors, cut a large cross and fold back to create a planting circle. Plant the shrub into the space and then fold back the membrane and cover with chippings.
The membrane will keep moisture in and weeds out and if you cover the whole border with the membrane, the amount of weeding will be negligible.
The membrane is not really noticeable with a mulch of bark on top and using a membrane will reduce weeding by about 95%. The almost total lack of weeding is the big plus for a membrane. Bark deteriorates over time and will need periodic renewal.
Another plus point is that the blackbirds just love the bark and spend hours rooting around in the border, throwing the bark into the air whilst searching for grubs, and it is great fun to watch.
There are some disadvantages to using a membrane. It is more difficult to plant with a membrane in place, as each time you have to clear off the bark and cut a hole, which means it takes more time. Also, it can restrict the natural spread of some plants as the hole you cut into the membrane is the space for the plant. Those plants which are self seeding cannot seed into the soil so it limits self seeding plants, which may or may not be a disadvantage.
Below image left is a weed suppressing membrane in situ with a hole cut in it to plant through. This type of membrane is available from Crocus. On the right, I have completed the border with planting and a layer of bark over the membrane.