Tony, "hypothetically" speaking, I would put the cuttings in the carry-on, and if they catch it, don't argue, and let them chuck the cuttings.
But there are SOO many available varieties right here, why take a chance?
If it were a matter of preserving a heritage, family tree, I might feel justified, and explain my reason to the authorities if I got busted.
Some things are worth fighting to preserve.