Getting a branch's time of creation

Hello,

I am trying to find the time at which a remote branch was created, so that I can use the '--since' option in git log to limit the commits to only ones that were created for that branch (read below to see why I can't use 'git log <branchnname>). So my question: does git remember the time at which a branch was created, and how can it be listed?

NOTE: Once I clone a repository that contains Branch1 (which will have its
own commits as well as commits from the master branch), I create Branch2 in
the clone to track Branch1. Branch1 will have commits before the cloning,
and Branch2 will have its own commits after the cloning, but I want to list
both. The way I am thinking of doing it is to list all commits for Branch2,
and then limit the commits to only ones that were created after Branch1 was
created.

If anyone has suggestions on doing this alternatively, feel free to pitch in. Thank you. Jawad.