In Little King's Story how do you beat Giant Frog Yvonne?

In Little King's Story how do you beat Giant Frog Yvonne?
The Giant Frog Yvonne is the Guardian of the Upchuck Forest.
Defeating it will unlock the Hunter's Hut, where you can train animal hunters.

This Guardian has 4 attacks:
1. It can leap forward, lunging at you.
2. It can spit poison out of it's mouth and create spots of poison on the ground.
You can avoid this attack all the time by hiding behind the tree near the entrance.
3. It can leap high into the air and perform a ground pound. After it performs a ground
pound, it is the best time to attack, because it will take a long time to be angry again.
4. The last attack is the nastiest of them all. If you see the frog look to the sky,
you better run because it is about to stick its tongue out in front of it. If anyone's in
the way, the frog will swallow them whole, killing them straight away.

This boss is particularly hard because it almost always charges up an attack immediately after the last one.
It is hard to beat this boss without losing at least one member of your guard.
Personally, I won with one person dead. Luckily, it was just a farmer.