Rav Pinhas Zevihi (contemporary) writes (listen to audio recording for precise citation) that one must make a point of reciting Birkat Ha’ilanot – the Beracha over the blossoming of fruit trees – as early as he can during the month of Nissan. Once Rosh Hodesh Nissan arrives, one should endeavor to find two blossoming fruit trees and recite the Beracha without delay.
Rav Zevihi emphasizes that one should not delay the recitation of Birkat Ha’ilanot even for the sake of reciting it together with a Minyan. He relates an incident where on Rosh Hodesh Nissan Hacham Ovadia Yosef saw two blossoming trees outside his window and inquired as to whether they were fruit trees. He was told that one was a plum tree and the other an orange tree, and he immediately jumped out of his chair and announced that everyone should recite Birkat Ha’ilanot. He recited the Beracha with immense love and joy, and afterward he announced, "Baruch Hashem, we had the privilege of reciting this Beracha at the proper time and in the proper fashion" ("Bi’zmanah U’be’hidur"). Even though there was not a Minyan in the room, Hacham Ovadia nevertheless insisted on reciting the Beracha immediately at that point, without delay, and considered the recitation of the Beracha on Rosh Hodesh Nissan as the ideal performance of the Misva.
Thus, as soon as the month of Nissan begins, we should all make a point of finding blossoming fruit trees and reciting Birkat Ha’ilanot, without delay, even if this means reciting the Beracha alone.
