I have written before about being somewhat of a hoarder when it comes to art and craft supplies.
So there is no difference with faux flowers and natural materials.
I see things I like and I stock up.
Nowadays there is such a huge selection of beautiful, life-like natural items...flowers, twigs, leaves, etc...
I am like a kid in a candy store.
I like to find unusual uses for them...sometimes I take the flowers apart and use the petals on their own...layered, they can look like fish scales for a whimsical mermaid sculpture...or can be a great base for photographing small items like jewelry.
If you buy off season they can be very affordable too.
I try and go in with an open mind...not looking for anything too specific and just see what I find. It's like a surprise!