Large trench for hedging / shrubs

Hi everyone. I hope you are all well especially during these strange times. Like most of you, my family and I have been making good use of the garden and I'm now thinking of planting some hedging. The trouble is I have two sides of my garden to plant with hedging and both span approx 200 ft.

The advice I've had thus far is to dig out an entire trench. Is it really that necessary to dig a trench (I've seen plenty of new hedging around the country side that's just planted on top of grass)? Is so, would anyone please recommend some tools and perhaps even some equipment I could use to make the process easy? I'm especially looking for ideas on how to dig a wide trench with a straight edge. I plan on making a trench, planting, and then using a composted bark mulch. I don't like using plastic membrane. Does this sound ok?

My apologies for obvious sings ot naivety with my post. Thank you for any help

 

Not that much in favour of planting a hedge in a big trench myself. I think it leads to too much soil being turned upside down and disturbed to be good for the young plants settling in. It also involves a lot more digging. I think it is better to just use a spade to make an individual little hole in the ground just to fit the roots of each hedge plant. Here is a video clip were I show my planting of a laurel hedge in spring. The ground where you are putting the hedge would be easier to dig if the vegetation is killed off before digging and the hedge will get growing better more quickly if it does not have to compete with other plants. A wide head pick or mattock is good for clearing vegetation from where you are going to plant and loosening the ground a bit if you don't want to spray with herbicide. The one I find easy to use is shown in this video clip. You will probably need to weed out any competing plants for the first year or so anyway. Better to plant in autumn or spring as well as the shorter days and wetter weather let the plants settle in more easily. You can also get bare root hedge plants that are cheaper than potted ones then. If you have a problem with working to a straight line a piece of string between two pegs or stakes can be set up to give you a guide to work to but when the hedge grows a bit I don't think you would notice a plant being slightly out of line which is helpful in case you hit a stone and can't plant exactly where you would want to.
Happy gardening!

 

Thank you very much. Very informative and something for me to think about