Green leaf litter, even when oven dried, tends to break down rather quickly compared to naturally dried brown leaves. I'm sure if you scoured your tree, you could find some brown leaves. Barring that, you could break a small branch, but leave it attached to the tree, and the leaves will dry up.

 

Thanks for the response. I'm gonna hold off then. I was able to get some magnolia from a friends tree, I'll use that for now and try to collect a bunch of leaves over the fall.