Wedding centerpieces start with interesting greenery. I adore salal (sometimes referred to as "lemon leaf"). It is long lasting with it's solid green traditional shaped leaves.
The leaves actually twirl around the main stems and you can cut off to short laterals.
Bury those deep into the foam to secure them.
Give the stems as long as you can . . . if you wish you can have two leaves on the insertion.
You want to be careful to always face the "topside" of the leaf. The way the leaf attaches to the stem it would be easy to flip the leaf over so the underside shows.
Scatter them around the arrangement, not exactly perfectly balanced - but with similar coverage on all sides.
You can see how such different greens can create different textures, making a great combined look.