Cabbage in the Mail

The first of the bunnies seed orders arrived today, a package of drumhead white cabbage containing 200 seeds. The rabbits are debating right now if they should try to plant it in the garden now, or if they ought to arrange the purchase of dirt and a long pot so they can lag it inside to grow this winter. Has anyone heard any bad things about possible invasive traits of this cabbage? I don't like how fast it arrived either. That's sure to be a bad sign if the rest of their stuff shows up as quickly.