You asked about ethics-- You, legally & ethically, owe him for the
plants. If I were you I would offer to pay for them.

You don't owe him for the plants, because it wasn't your order. To give your
conciense a rest, (and it's the nice thing to do) you should attempt to
contact the seller to see if he would like the pips returned. I know you're
having communication problems, but if he answers back most likely he'll let
you keep them. It would most likely cost him more money to collect them from
the PO than to just let you keep them. Even if he wants them back, it's no
great loss at $1.29 postage (He might even offer to pay it). If he doesn't
answer, well you tried, not much else you can do.


Don't forget to reflect his lack of quick communication when you leave
feedback for him.

Give the most detailed feedback you can, so others have a good idea of what
kind of seller he is.