I have a few tall spindle trees that I planted in the spring that are doing well but i have a Blondie apple that has grown many side branches off of one of the feathers. The feather in question has grown much larger than the leader should I trim this off now or wait until the tree goes dormant?
Assuming your tree will go dormant soon, dutch cut it when dormant.
I agree with TCT. In the future, you can remove such branches as soon as they become obviously oversized but the branch is serving wood and roots by now and not pulling much energy from the rest of the tree.
I haven’t heard the term dutch cut before but assume it means to leave a bit of extra stub so you will get a replacement branch for sure. I think I’ve read it termed “bench cut”.