The thought of Autumn sometimes brings mixed feelings. Some people embrace the cooler weather, even finding it energizing. Still others feel a certain sadness at facing the end of the warmer Summer weather. For most people that have a yard, fall brings to mind one thing particularly: Raking leaves.
While raking leaves is almost a rite of passage (I was the assigned leaf raker when I lived at home!), it is certainly not something that absolutely has to be done. There are some important ecological benefits of leaving the leaves, not to mention benefits for the gardener.
Benefits of Leaving the Leaves
Nutrient Cycling
The leaves of trees and shrubs are what produce energy for the plants, through the process of photosynthesis – Maybe you remember this from your 6th grade science class! The leaves use energy from sunlight and water from the plants’ vascular system, to produce glucose for the plant, giving off oxygen as a byproduct.
As the trees grow, they draw up nutrients from deep in the ground and utilize carbon from the air to form new leaves and twigs. These micronutrients and carbon are still in the leaves once they turn and drop in the fall. Raking the leaves and putting them out for trash collection means that you are depleting the soil of nutrients, especially micronutrients!
Autumn leaves make for a great mulch – I use them to mulch the beds in woodland areas. You can shred them if you want them to break down quicker and keep them from smothering plants, but I find for most native woodland plants this isn’t an issue.
Caterpillars – Next Year’s Bird Food
If you have any common native hardwood trees in your garden, especially oaks, this is another reason to leave the leaves. Most native hardwoods support a huge variety of Lepidoptera, which is the classification for moths and butterflies. Their larvae, which we know as caterpillars, are one of the main foods for songbirds, especially when they’re nesting in the spring.
These caterpillars pupate in the fall and drop off with the leaves, where they complete their life cycle in the ground. The new moths and butterflies hatch in the spring, and removing the leaves in the fall means that you’re getting rid of next spring’s caterpillars – If you like having songbirds in your yard, it is important to do everything you can to make sure your garden is producing plenty of caterpillars!
Moisture Conservation
Left on the ground to act as a mulch, fallen leaves do an excellent job of conserving moisture in the soil. Moisture evaporates from exposed soil much more quickly than soil covered with plants or mulch – If you have a dryer soil type to start with, removing the leaves can result in the need for supplemental irrigation to mitigate the risk of your plants dying.
Frost Protection
A thick layer of leaves acts as a great insulation barrier between the soil and the air – In the winter months, frost can cause the soil to heave, forcing plants out of the ground. A layer of leaves reduces the effects of frost in the soil, protecting your plants.
In our garden, I notice that woodland groundcovers like Tiarella and Phlox stolonifera are very succeptible to frost heave – In one new planting where I hadn’t put a leaf layer, I lost most of the plants I had planted. In another spot where I managed to pile leaves up, the plants really filled in the following spring, due to both the reduced effects of frost and the additional soil moisture provided by the mulch of leaves.
Why You Might Want to Rake the Leaves Anyways
HOA Requirements
Not everyone has the advantage of living on a standalone property. As unfortunate and sometimes infuriating as it is, if you are in a subdivision, you likely have an HOA to deal with. HOA restrictions can sometimes be both arbitrary and strictly enforced – You may not be allowed to leave your leaves due to the “untidy appearance.”
If you do have a restrictive HOA to deal with, you can definitely still use the leaves – I would shred the leaves and use them as a mulch for your flowerbeds, or just compost them in an out-of-the-way spot.
Consideration for Neighbors
Not everyone likes leaves blowing around – If you have neighbors, they may not be too keen on having leaves blowing across their yard all winter. In this case, the best option may be to shred the leaves before you use them.
If your efforts to make your garden more sustainable and wildlife-friendly are met with dirty looks by your neighbors, a little explanation and education may be warranted – Refer them to Paddle Creek Gardens to get them on board with the idea!
Other uses for your leaves
If you have to rake your leaves, by all means don’t let them go to waste! Please don’t just bag the leaves and set them out for trash pickup, off to fill up the landfills. Your trees worked hard to pull nutrients out of the ground, don’t let them down by letting your leaves go to waste.
We have an almost 4-acre property, but the trees I’ve planted have only just now started producing enough leaves to work with. The only trees on the property when I moved here in 2017 were Callery Pears and Blue Spruce, so I didn’t have a good resource for autumn leaves like I was used to in the last 2 houses. Because of this, autumn leaves are a rare commodity for now – I envy people with mature hardwoods to work with!
Use Your Mower to Shred the Leaves for Easier Use
If you don’t want to do anything with your leaves, you can mow them up – the University of Michigan states that you can mow up to 6 inches of leaves over your turf without any ill effects. Indeed, if you leave them without mowing, they will smother and kill the turf grass, but shredding the leaves with a mower helps them break down more quickly, releasing nutrients and organics to the grass for a thick, lush lawn.
If I have time, I like to shred leaves with my zero-turn mower. I then use my walk-behind mower with the bag attachment to collect them and dump into a wheelbarrow where they can be used for compost or mulch. This method leaves quite a lot of chopped up leaves in the grass, but that isn’t a problem. They quickly bed down into the turf where they decompose quickly.
Compost the shredded leaves
Since I don’t have many leaves to work with in the first place, I have only composted our fall leaves once. I decided not to do that again until the hardwoods I’ve planted grow large enough – I didn’t have enough shredded leaves to mulch all of the landscape beds that year and I lost a few plants to frost heaving!
If you do have an abundance of leaves, adding the shredded leaves to your compost is a great way to use them – Good yard waste compost (“Waste” is not a very good word in this context, I’ve always thought) is loaded with nutrients, and using it in your vegetable garden really boosts your garden’s productivity.
Use the shredded leaves as mulch
My favorite way to use fall leaves, if I have the time, is to shred them and use them as mulch – I always collect them after shredding them by going over them with my walk-behind mower with the bag attachment. I just dump the bags into a wheelbarrow and spread them over the landscape beds. I usually get a few grass clippings along with the leaves, but these are good as well.
If I can, I always like to shred the leaves – I find that when I use shredded leaves as mulch instead of whole leaves, my plantings do better the following season as they are able to push up through the leaves more easily. I also find that they don’t blow around in the winter like they do if I leave them whole – Though I’ve been working on planting trees and shrubs, we still have a lot of open space for leaves to blow around.
I do have some areas where I like to leave the leaves whole – Under our oak trees, especially, I like to leave the leaves whole since shredding the leaves runs the risk of killing the caterpillars that would overwinter in the leaves. I try to keep our landscape as caterpillar-friendly as possible to help the songbirds in our yard.
I hope I’ve given you some ideas for what to do with your fallen leaves this autumn – Try some of these tips this year and see how your garden benefits!
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