Glue for Leaf Collage?

[JRsandCoffee]

I'd like it to last. Parents are moving house and planted a lot of trees where they are and love them all so want the collage to last at least a few years! Thanks :-)

I've used PVA glue for pressed flower pictures. I wonder if acid free would be better for it to last a bit longer. Is your collage going to be in a frame with glass? It's a lovely idea

Hoping to frame if it is good enough! Thanks for the suggestion, hadn't even thought of acid free!!