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 it's roots and grow deeper roots, but keeps other tree roots from choking out the one I planted.
Growing Asparagus is quite easy. I have grown asparagus from seeds and that too in a pot! It is quite a hardy plant and tolerates cold winters and dry spells as well. Just don't overwater it. This year I am planting the crowns from my potted plant in a raised bed along tomatoes and coriander as both the plants discourage each others pests.
When To Plant In Your Garden....