Weed matt and gravel

[Rinkydinkypink]

Ive got a very large area of boggy flowerbed with established trees. TS a nightmare! A we can't dig it because the clay is so heavy. We've tried everything from stones to sand to masses of organic matter and yet still it's unusable land. Were going to keep the trees but gravel it. It's the most effective way of managing the area on a budget.

Do I need to weed it before I put the Matt down?

No. If the weed mat is good (use double thickness) it will prevent light reaching the weeds underneath and kill them.
That said, it's worth a cursory weeding first to make the surface more even for laying gravel on.