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Fallen Leaves and Tree Maintenance in Autumn

The glorious show of autumn color is transitioning to the familiar browns and barren trees that will continue through winter. Two Purdue experts recently offered advice on what to do with fallen leaves, and some maintenance practices that should help landscape trees, especially more recently installed trees, to have a better chance for long-term success.

“Unless excessive, moderate amounts of tree leaves can be simply mowed and mulched into the turfgrass canopy with no detriment,” said Dr. Aaron Patton, Turfgrass Extension Specialist. He said that it is important to rake leaves when there are many leaves on the ground (so many that you can’t see the turf underneath) so that heavy layers of leaves will not shade out, smother, and kill turf. However, when only a moderate number of leaves are on the ground, you can use your mower to mulch them back into the turf.

Dr. Patton cited Purdue research results that support these recommendations:

  • Tree leaves (both oak and maple) can be mulched without any detrimental effects on the soil or turf and usually result in improvements in soil structure.
  • Mulching leaves into the turf will not increase thatch or disease.
  • Leaves have no effect on soil pH and no measurable effect on nutrient availability.
  • Mulching leaves will not result in increased weed pressure and some recent research in Michigan even suggests that mulching leaves back into your lawn can reduce dandelion populations.

Find Dr. Patton’s original article at:

Now to the trees from which those leaves fell.

Ben McCallister, Purdue Extension urban forestry specialist, said that to give your trees the best chance to survive the winter and better thrive next year there is an assortment of activities available ranging from DIY projects up to calling in an ISA-certified arborist to help you out, including mulching, fertilizing, watering, limited pruning, preventing winter injury, and inspecting.

“Adding a 2-3-inch-thick layer of mulch will better maintain moisture levels and buffer extreme temperature changes in the soil and will add some organic matter too,” said McCallister. “Try for at least a 3-foot radius from the trunk and make sure to leave a 2-inch or so gap between the trunk and the mulch.” He cautions: “Remember, no volcano mulching.”

“That mulch you just added will add some organic material to your soil as it slowly breaks down, but an autumn fertilization can benefit your trees too,” he said. “Adding a slow-release fertilizer in the fall helps provide a nutrient boost over the winter, can promote root growth, and better prepare your tree for spring.”

“You can water up until the first freeze, but make sure soils are just a little damp and not soaked,” said McCallister. “Evergreens in particular will benefit from slow deep watering 1-2 times a week until the soil freezes.”

“Now is a good time to prune out any dead, damaged, or diseased limbs in your trees,” he said. “If you have access to hand saws and pole saws or pruners, you can remove smaller branches or those closer to the ground.”

“Sunscald or southwest damage occurs on young and/or thin-barked trees in the winter,” he said. “Trees can also incur damage from deer during the rut.” He recommends using a white corrugated drainage pipe as a tree guard that can be found at most home centers. Remove it in the spring.

Finally, McCallister said that visual inspections can be done year-round, but this time of the year it might be easier to see changes in your tree as leaves are falling and the canopy becomes more visible. “From the ground up to the canopy, some of the things you’re looking for include fungal growth around the base of the tree, any sort of damage on the main stem or branches, premature leaf drop or color change, and branches that are dead, cracked, diseased, or seem weak,” he said. “Any concerns you find are also great information to share with an ISA Certified arborist.” 

Find McCallister’s original article with more detail at:

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