Question
Hello, I have had wonderful success with my 3 arborvitae in large plastic containers for over 10 years. Beautiful, tall privacy on a city deck. Well,the summer heat did them in and I am "trying" to get them out of the pots and put in new ones.
I cannot get them out of the pots. Pulling, digging down the sides, shaking upside down (with help) Any advice? I do not want to throw away the pots, too big and not cheap.
Thank you for any advice.
Bob

Answer
Over 10 years in the same container. I can picture the roots and soil from here. At least one thing makes it easier. You are removing and not transplanting. I have transplanted and saving the plant along with the container was not always successful.

Here are some tips you can try.
Dry the soil as much as possible. The soil shrinks when the moisture is removed, and pulls away from the sides of the container. This can be speeded up by using heat and wind.
Run a large flat blade around the inside of the container so the soil has no attachment to the sides.
Turn the container on it's side and roll it and shake it to loosen every thing inside.
If possible cut some of the remaining roots into loose pieces that will fall apart easily.
Next get a strong friend to help you. One pull on the container and one on the plant and soil. If the plant has been loosened properly it should slide right out. If their are still stubborn roots in there then the extra muscle should pull them out of the container.  
If it still remains, then cutting is the only solution. This means taking a very sharp cutter that won't be damaged by soil. If it is mechanical then be very careful to be in control of the power. Cut down as far as you can and keep trying to pull the plant out. If the roots are attached on the bottom of the container, then the only solution is to carefully cut to the bottom of the container to remove the roots that are attached there.

One more tip....don't wait 10 years to transplant.  Even if you use the same container, give the tree a careful root pruning every three to five years and give plenty of fresh soil. Both you and the plants will benefit. I would guess that these trees were stressed before the hot weather hit them. They may have survived if they were healthy. Best time to root prune is in cool, damp weather in March or April.