Time needed for the plant roots to establish in the pot will depend on the species and the size of the pot. Only container soil should be used in containers. Most garden soil will not drain well enough. Before I offer any plant for sale I will knock it out of the pot. If the roots do not hold the mix together it is not ready for sale. Al

I would pot the a little befor the sale and tell the people to sell them and tell people to plant right away. You can cut back a good amount. I had a sale last yr. and will have one in May. so will do the same here.

The size of the root ball and the branches and leaves should be in balance. For all you cut in the roots, do so in the top.

Penny

I will disagree with some of the above advice.

Try to cut off as few roots as you can. Mark the pots so the buyer knows they were just dug up.

Do not cut the tops, even if you trim the roots. This is no longer the best advice for transplanting trees or shrubs.

You should not use 'container soil'. Use the soil the plants are now growing in. These plants will be going back into the garden at their new home. Having a bunch of unnatural soil around the roots only makes the transplanting harder on the plants.