Fall in the Land Between
Autumn means beautiful displays of vibrant colours, a cool breeze gently kissing your cheek and leaves blowing around your property. It is a time of seed caching for rodents, travels to hibernation sites for turtles, mushrooms fruiting, and joyfully wearing a warm sweater. Autumn is also a time of survival preparation as species search for and carefully choose locations that will provide them with the vital shelter needed to protect themselves from harsh winter temperatures. Some such locations, like fallen leaves and other dead plant matter (remaining wildflower stalks, etc), are often overlooked by humans yet are irreplaceable in their importance in natural cycles and the protection they provide to animals. Numerous species of animals, including salamanders, bees, moths, and butterflies, overwinter tucked away from bitter temperatures under the effective insulation of leaves or the walled protection of plant stems. However, the safety of their winter hideaways become threatened when people decide rake leaves or cut off flower stalks and remove them from their properties. Unfortunately, this results in the death of many of our pollinator friends and the removal of precious nutrients from ecosystems! Below are some of the topics that will be addressed in this page:
If I leave the leaves will my grass die? What do I do?
It is true that keeping a thick layer of leaves on your lawn it can stress your grass, however there are alternatives that will not threaten your lawn and will keep nature healthy!
- Rake your leaves into piles, but do not remove them: If you are very eager to remove leaves from your lawn, but also care about wildlife, consider raking the leaves into piles and then allowing the piles to remain on your lawn all winter and spring. This will allow the leaves to benefit animals, while also removing them from most of the lawn. Remember, just like we need insulation in our homes to survive the winter, so do animals!
- Rake leaves into garden beds and leave them: This is a great way to add nutrients to your garden and to help protect your plants from freezing temperatures (even native plants can perish in the winter if the cold penetrates into their roots)! These leaves will also act in a similar way as landscaping fabric or wood chips meaning that they help to suppress weed growth too!
What about mulching?
Many insects, including moths and butterflies which form cocoons/chrysalis, overwinter in leaf litter, with some even disguising their cocoons to look like leaves! This means that if you mulch leaves you are likely damaging or killing them. Therefore, this option is not preferable, however it is better than bagging and removing leaves entirely.
Is removing leaves that have fallen in the water bad?
Leave litter can be an extremely important source of annual nutrient inputs for water bodies, seasonal changes in water chemistry and shelter for many aquatic species. Thus, removing leaves from your lake is removing an important input source for many creatures! Leaves typically decay in water even faster than on land (usually take 6-12 months on land), so they will disappear naturally in no time!
When is it okay to remove leaves completely?
As previously mentioned, fallen leaves provide a rich source of nutrients for soils and decomposers, and vital shelter for overwintering animals. This means that leaving the leaves to decay naturally and completely is the best way to support nature. However, if you must remove and dispose of leaves please wait until night time temperatures consistently reach 10°C (typically May). By this time most of the animals using leaves for shelter will have awoken and emerged from their winter hideouts.
When should I cut down dead plant and flower stocks?
Just like the insects cozying up under the leaves, there are also other species taking a winter snooze in plant stocks! In autumn, before the snow falls, many insects burrow into dead plant stocks where they will remain until the night time temperatures consistently reach over 10°C. Please allow dead stocks to stand until the middle of spring to allow these animals to survive! In addition, leaving standing native wildflower stocks throughout the winter also makes seeds available for hungry birds!
When spring does arrive and once nightly temperatures are over 10°C, lop off only the tops of stocks leaving them 8-24 inches tall instead of cutting them to the ground. This creates habitat for nesting pollinators who will lay eggs inside the stocks even more pollinators in your garden!
Interested in learning more about how to create overwintering and nesting habitat for pollinators? Check out this great document titled "Nesting & Overwintering Habitat for Pollinators and Other Beneficial Insects" by Xerces Society for Invertebrate Conservation.
Written by: Fallon Hayes, Communications and Education Specialist
- Leave the leaves! Why raking leaves can be damaging to the environment…and your lawn. By Mary Jane Proulx
Duan, S., Delaney-Newcomb, K., Kaushal, S. S., Findlay, S. E., & Belt, K. T. (2014). Potential effects of leaf litter on water quality in urban watersheds. Biogeochemistry, 121(1), 61-80.
Pope, R. J., Gordon, A. M., & Kaushik, N. K. (1999). Leaf litter colonization by invertebrates in the littoral zone of a small oligotrophic lake. Hydrobiologia, 392(2), 99-112.