Complete Novice seeking advice!

Hi,

being a complete novice at gardening am after some valued advice if I may!

Basically my garden is on a slope and we have a raised deck area from the back door, either side of the deck is a trip of 'bedding' about 2foot wide. Want to shingle this as don't have the time or inclination to start weeding/growing things!

My plan is to put some polythene down to kill of the weeds etc that are there, then lay the bed of shingle over the top.

My problem is that on one side I have two 'trees' called Photinia x fraseri 'Robin Red'. I planted these a couple of years ago to create a shield from neighbours, they are currently about 7 feet tall. I want to keep these and am worried about the polythene/shingle not allowing rain water to get in and keep them alive.

Any ideas of what to do? I thought maybe lay the polythene but have a circle around the trees about a foot wider than the tree, then shingle around the base of the tree. I understand I will still need to weed this small area, but will the rain water etc get through sufficiently?

Sorry this is such a long post, look forward to your thoughts.

Many thanks

why not use weedblock fabric instead ? it lets water through but blocks light to stop weeds - I used some last weekend which I got from B&Q which lasts for up to 15 years (weedblock premium) - they also do stuff which lasts for up to 5 years (weedblock basic) but I wanted the heavier duty stuff ?