Is there any issue with buying fresh blueberries from a country outside Eretz Yisrael? How can you know whether they are orlah? Questions also applies to any fruits grown outside Israel..
There is no issue or concern of orlah when buying fruits growing outside of Eretz Yisroel, because the rule is that “safek orlah bchutz la’aretz lkula”. Any doubt regarding orlah on fruits grown outside of eretz, we rule leniently and assume that it isn’t an issue. Therefore we will assume that the fruits are indeed not orlah.
Tractate Orlah 3-9.