[O] ignoring subtrees scheduled in the future

[Alan Schmitt]

Hello,

I'm planning some projects for next September, and I don't want to see
them in my agenda till then. These projects have a schedule date in the
future, but none of their subtasks have one (there are many of
them). I've found the very nice

(org-agenda-skip-subtree-if 'scheduled)

option for agenda views that skips them, but it works even for tasks
scheduled in the past. There does not seen to be a 'future option for
skipping subtrees, and the (org-agenda-todo-ignore-scheduled 'future)
option only seems to work on single entries.

Do you know of a way to hide some subtrees until a given date? I'm happy
whether it uses a Scheduled flag or something in the property drawer.

Thanks,

Alan