I am in Michigan and my asparagus plant is now (late October) a giant fern. Do I trim this fern down or just leave it alone for the winter??? This is in the garden and we use it for asparagus not as a decorative plant.
It is best to leave the fern intact until it is yellow. As long as it is green it is still sending energy to the root. Once it turns yellow you may mow it off or leave it through the winter. Some leave it so that it catches snow and helps insulate the root below. If you leave it you can then mow it off early next spring.