Q. On the last day of sheva brachoth, can you still say the brachoth after the beginning of the shkiah and if it is permitted, for how long?

A. Taz (E.H. 62: 3) quotes Maharal’s opinion that you can recite sheva brochos on the night following the seventh day, however, most Poiskim disagree (Ginas V’rodim 62: 12, Otzar Haposkim 62: 30: 2, Nitey Gavriel – Nissuin 2: 109, et al.). Sovea Smochos (1: 3) rules that even if birchas hamazon ended before sunset, the sheva brochos should not be recited afterwards. Moreover, if there is no time to recite them all, none should be said.

Oholey Yeshurun quotes Horav Moishe Feinstein’s Zt”l opinion that they could be recited up to forty minutes after the onset of the shkiah.. Sefer Ben Hashmoshos permits only seventeen minutes after.

Horav Shlomo Miller’s Shlit”a opinion is that after the fact, they could be recited fifteen minutes after the shkia, (see next answer)

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