I listened to a gardening program that suggested leaving leaves on the garden in the fall. I have a layer of oak leaves covering most of the garden, with heavy layers near sensitive plants (rhododendron). My garden gets medium sun. The crocuses are just starting to emerge. Should I remove the leaves? If so, when and how? (by hand is my norm) My garden has a lot of bulbs, hellebores and a few other spring flowers, followed by other perennials in the summer.
Thank you for contacting Toronto Master Gardeners. There has been increasing interest in “leaving the leaves” in recent years, and for good reason. Leaf cover offers insulation and protection not only to plants, but also to beneficial insects that overwinter in the ground and in leaf litter. Leaves act as natural mulch, which helps retain soil moisture during summer dry spells and can also help suppress weeds. Once broken down, they add organic matter back to the soil.
However, a very thick layer of leaves can certainly hinder the emergence of spring plants, and oak leaves generally take longer to break down than, say, maple leaves. Try gently raking or pulling back the leaves in spots where bulbs and other spring plants are emerging. Once the weather warms to consistent daytime temperatures in the mid-teens (celsius), you can rake the leaves into a pile, or place them inside a plastic garbage bag, and let them decompose away from your perennials. Waiting until the outdoor temperature warms up will give overwintering insects an opportunity to emerge before their winter protection is removed. Once leaves have broken down, they can be added back to the garden. In the upcoming fall, if you have the means to do so, you may want to consider shredding or mowing your leaves. Shredded leaves decompose faster than intact leaves and, if left on garden beds, they will allow bulbs and other plants to emerge from the ground more easily come spring.
For more information, please feel free to visit the following links:
Leave the Leaves (North Carolina Cooperative Extension)
Why you should leave the leaves (David Suzuki Foundation)
“Leave” Them Alone: Lawn Leaf Management (Virginia Cooperative Extension)