Until when can u make Brucha on a tree?
L’chatchila the bracha should be said during Chodesh Nissan, however if it wasn’t said, then the last time to say the bracha will depend if the person has already seen budding or growing fruits that year. If one did not see any budding fruit trees the bracha can be said as long as the fruit are still growing, but still not edible. If however you did see budding, then the bracha can be said only until the fruits start to grow.
O:CH 226, M:B 4,5.