I am toying with the idea of taking my horse to a few jumper shows. He is a Kiger Mustang, and in all other shows it is fine to leave his mane completely natural - uncut and unbraided. Is that okay for jumpers? I’ve heard that unbraided is fine - but is a long mane still okay?
No need to braid for jumpers. Long is fine as long as it doesn’t interfere with your hands/reins.
There are no rules only conventions.
As long as it doesn’t interfere with your hands, reins and anything else for that matter, you can do mostly ‘anything’ with it.
Yes, a long mane is fine.
But, you could always do a running braid if you want to look a bit more conventional. Just google it and you will find many videos showing how if you don’t know.