This is actually a great idea about gifts. And I am interested in what plants we can grow this way. Herbs sounds very good. We can only grow things in pots, though, and on a small space, since we have a small apartment on the 13-th floor. A garden there seems like a miracle almost ;)
Most plants can be rooted in water, but if your space is limited then maybe herbs are the way to go because you can eat them too.