Q. If somebody visited South America during our winter and made a brocho there for the new blooming trees (in their spring). Does he have to repeat the brocho when he sees new blossoms in the northern hemisphere?

A. This brocho is uttered once a year only, regardless of which part of the world one recited it first.

Shaarei Yemei Pesach, (ibid.) mentions Tu Bishbat as the beginning of the year for this brocho, However, Horav Shlomo Miller Shlit”a is of the opinion that the year is counted from Rosh Hashonoh.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a