I'd leave her tied all day.
If I get a horse with a tying problem, I tie it.
If you have trees with thick sturdy branches throw. Long rope up there and tie the horse to it.
Make the rope long/low enough that the horse can hold its head normal. And leave.
If no tree just tie high so if if rears it can't get a leg in the rope.
Tie it, till it chills.
My gelding will stand tied to the trailer ALL day at a show and not so much as fidget. He goes to sleep. My filly likes to pull back if she gets a fright but usually stands quietly... I'm going to be working on the pulling back issue when I can, just don't have the facilities to do that at present.
Also... tie solid, NOT to twine, especially if you're going to leave them tied for a long time. If they pull back and get free they can learn to ALWAYS pull back. Rope halters are best because they don't break easy, eliminate all metal points [they are weaknesses] meaning get a lead with a removable clip and remove it.
With a horse that refuses to stand still when tied you want to reinforce that it CANNOT get free so it might as well not fight it.
I have tied to fence strainer posts in the past especially with my filly when she was going through her phase of pulling back every time she was restrained in any way. These posts are a foot thick minimum and dug down between 5 and 6 feet so they're not going anywhere... certainly not with the strength of one horse. Rotten ones won't hold, so a tree is better if you have one, but if you don't, a big thick wooden post will do.
Whatever it is you tie to must not EVER be able to break under the force of a horse pulling, leaning or pushing on it!
Another option if you have two big solid trees and a long strong rope is to string up the rope between the two trees and tie your horse to that - it has to be above horse head height so they can't get caught up on it - and again, eliminate all metal. The rope will give some if the horse panics, but it's not going anywhere if you pick a strong enough rope, and your horse is highly unlikely to injure itself.
If you tie above horse head height you eliminate most of your horse's leverage and therefore most of its strength.