MISHNA BERURAH YOMI MISHNA BERURAH DIRSHU JULY 6

S"A 229 Mishna Berurah sif katan 8
Initially one shoud perform the mitzvah immediately as one can as soon as possible after the event one can make the blessing until the 3rd hour of the day

Mishna Berurah Dirshu Chelek 2
Introduction during the month of Nisan one should make a bracha on blossoming fruit bearing trees the bracha is shelo caser bolmo kulam ibra bo brios tovos lhanos bahem binei adam
Q:What if someone didnt say the bracha during Nisan can he say the bracha in a different month

A:Mishna Berurah says yes M"A and Sharei Tzion say no