our bay trees leaves are curled, very dry and don’t look healthy. The plant has been in a pot, outside and healthy all summer

Question

The pot was in a hessian sack with a plastic bag around so possibly no drainage for the water/moisture

Answer 1

This sounds like a fungal issue, which could have definitely been the product of the bag. You will likely have to repot into fresh soil, and when you go to water it in, then replace 1/4 of the water with peroxide to kill off any of the remaining infection.

After the treatment and repotting, you can continue to care for it as normal. This article will help: https://www.gardeningknowhow.com/edible/herbs/bay/container-grown-bay-trees.htm