Raising garden level

Thebigeasy

I've about 40-60 ton of subsoil/topsoil that I dug out from my back garden, my plan is to raise the front garden by about  roughly 150-200mm.  

The lawn I'm not bothered about as I will cover it over with heavy polythene to keep any weeds down before adding and turfing I need to raise the flower bed too or I won't see much of the plants behind the small retainer.

The small shrubs and flowers I can lift out easy enough I suppose, but will raising the soil affect my laburnum and rhododendrons and one other I don't know the name of.

Some pictures to give you an idea.

K67

I dont understand why the need for the plastic, unless you are intending to take it up before you lay the soil. If you leave it there without drainage holes you could end up with a pond. If you want to lay a membrane than a porous geotextile would be best.
Weeds will still appear in the earth you put on.
You can't raise the soil level around trees by more than 2 inches a year and that probably applies to shrubs. You could put an edging around them  to  keep the soil away.

Thebigeasy

K67 said:

I dont understand why the need for the plastic, unless you are intending to take it up before you lay the soil. If you leave it there without drainage holes you could end up with a pond. If you want to lay a membrane than a porous geotextile would be best.
Weeds will still appear in the earth you put on.
You can't raise the soil level around trees by more than 2 inches a year and that probably applies to shrubs. You could put an edging around them  to  keep the soil away.

Sorry should've been clearer, the plastic is to rot down any vegetation and kill any weeds as it will be lying for the best part of a year before removing it and adding topsoil and turfing.  

Would adding about 4" of decorative chips within  the  edging affect the tree or shrubs? 

K67

Adding a mulch around trees and shrubs is fine but it must be kept away from the stems. I usually leave a 2 ins gap but have no idea if that's enough but shrubs still alive!