There is much discussion in the Poksim today if to make a Blessing of Shehecheyanu when tithing today. The story goes, that when the Imrei Emes visited Israel, he met with Rav Kook and mentioned that he will be making the Mitzvah of separating the Ma'asrot for the first time, if so Rav Kook said, you can make Shehecheyanu as well. After a heated debate in which the Imrei Emes siding with the opinion of those who do not make Shehecheyanu, he got up and said, if the Rabbi of Jerusalem, was Posek that you do make a Beracha, I accept his authority and did indeed make Shehecheyanu.
Another possibility might be that the blessing they made was an extension of the Shehecheyanu made on purchasing a new home, clothing etc which they extended to be any happy occasion. There seems to be a consensus though with the Poskim that on eating a new vegetable or other non-fruit that Shehecheyanu does not apply (BaCH OH 235).