It Really is Better to Leave Some Leaves
Everyone wants an attractive garden. That’s good, because garden appearance always matters. But the pursuit of tidiness in the winter garden can go a bit too far. A common lament is “I didn’t get all of my leaves out of the garden before winter.” Or, in this day and age, “I don’t know what to do about the leaves that fell after my landscaper was here.” However, leaving some leaves in the garden can be good for the health of your plants. This isn’t an excuse to become lazy and certainly thick piles of leaves left in the garden over winter are not beneficial.
After the first hard freeze (below 28ºF), most annuals and perennials die back so that any remaining life is retained only below ground in their roots. Likewise, deciduous trees and shrubs lose their leaves, such that their energy and growth refocuses toward their roots.
An important balance for plant health is to continue to replenish water to the roots, while protecting them from extreme cold. If trees and shrubs don’t get enough water, they can suffer from winter burn and be affected well into the next growing season. If the tree roots are not mulched well, or otherwise insulated from the cold, then their growth can be stunted or, in the extreme case, the tree, shrub, or perennial might not survive the winter.
In a wooded neighborhood, many leaves fall each autumn, and depending on the species, they can continue to drop even into December. Thick layers of large leaves left in the garden are not good for allowing water and air to get to the plant roots, which means the large mats of leaves need to be removed. However, allowing some leaves to remain on the ground provides an additional layer of insulation to help the plants get through the coldest part of winter.
For some early blooming flowers (e.g., hellebores pictured above), a thin layer of leaves or leaf mulch can help protect the buds from cold exposure and damage. And some plants that are borderline perennials (not quite cold hardy), can survive the winter by covering their roots with some extra leaves or a pile of leaf mulch.
