Birkat A’ Ilanot
During the month of Nissan it is also traditional to recite Birkat Ilanot, a blessing at the sighting of the first blossoms on fruit trees. In Turkey, this was traditionally done during the week of medianos (Hol Hamoed). However, in the New York Metro area, we cannot usually see these blossoms until the end of Nissan or beyond. Whenever the calendar allows, typically after a Jewish leap year (5 years in every 19), this is a lovely custom. Lately, we have been saying this blessing on newly blossoming or sprouting trees of any kind on a hike the weekend after Passover.
Talmud - Mas. Berakhoth 43b
Rab Judah says: If one goes out and about during Nissan [in the spring] and sees the trees sprouting, he should say:
בָּרוּךְ אַתָּה ה', אֱלֹהֵֽינוּ מֶֽלֶךְ הָעוֹלָם שֶלֹּא חִסַּר בְּעוֹלָמוֹ כְּלוּם וּבָרָא בּוֹ בְרִיּוֹת טוֹבוֹת וְאִילָנוֹת טוֹבִים לְהַנּוּת בְּהֶם בְנֵי אַדָם
Blessed are you Lord our God, Sovereign of the universe Who has not left His world lacking in anything and has made in it fine creations and goodly trees for human enjoyment.
If a minyan is present, you it is customary to add psalms 122, 126 and 148 followed by a mourners kaddish.