Securing artificial grass to treated pine

I am installing an artificial grass path up a slope in my garden. It has timber edging - H4 treated pine 75x45 (with the same for cross support) and filed and compacted with blue metal dust (60mm).
I am now about to secure the grass and want to screw it down to the timber. I was thinking of using 25mm gal button head screws.
Good idea? Bad idea? Stainless timber screws? Stitching screws (not too sure what they are)? Tufcote treated pine screws? Appreciate any advice other than starting again!

would staples hold it and be hidden better?

Thanks for your reply.
Not too sure that staples would be strong enough - it is pretty thick material.

Urethane flooring adhesive is plenty tough and dries flexible.

Thanks for the reply
I think I need to tension it so I doubt that the adhesive would initially hold it in place.

Any views on the type of screw from anyone?

A panhead screw should do the job. You could add some adhesive if you feel it needs it

Thanks
Gal? Stainless? Tufcote?

Stainless or tuffcote would be fine . If you can’t find a big enough head in a suitable screw grade you could place a small washer under the screw to give a bit more surface area to the grass

Thanks Beardy - very much appreciated.