letiole, thanks for the information and sources. I thought there was some sort of legal way to import bulbs, as we have always declared the bulbs we brought in without any issue. (I also take import of live, organic products seriously as a potential threat to other ecosystem and bioindustries.) That is why what one vendor told me about a blanket ban puzzled me.
NilsHolgerson, also thanks for advice. I can get about 500+ mixed bulbs here for around 25 euros, maybe less. It is also the thought that they came all the way from Holland that makes them that little bit special. And of course they fit nicely into the 64kg weight limit (as if I ever have that much).