It's Simple to plant a plant Okame Flowering Cherry Tree
Dig a hole approximately twice the height and width of the rootball of your Mimosa Tree. Overall, the hole should be twice the size of the rootball. Spread out & unbundle the roots of your tree. Be sure to break up any solid dirt in the sides of your hole so that the roots can grow.
Making sure the roots are pointing downward, place the tree in the hole. Be sure that the tree is completely straight.
Fill the hole with dirt, then add water. Adding water will remove the air pockets that can dry out the roots and kill your Mimosa Tree's roots. Make sure that you keep grass several feet away from the base of the trunk, because it will compete with your tree's roots for water and nutrients.