Cut the bottom off a plastic pot to contain invasive plants bury in the ground. I have been doing this for a few years works great for containing plants that tend to spread, but that I still want to plant in the garden. This also works good for planting a plant in an area that tends to get filled with roots etc. from other plants. I will use a larger pot so that the plant can spread its roots and grow deeper roots, but keeps other tree roots from choking out the one I planted.