Brilliant red, yellow, and orange leaves are defining features of autumn. Driving down tree-lined streets, a quick trip to the mountains, and raking up a giant pile of fallen leaves evokes feelings of fall, even if we’re sweating while raking the leaves in our Atlanta-area landscapes. You may wonder, though: why do the leaves fall from some trees but not others?
Not All Trees Are the Same
Trees are separated and classified by their individual species, and they are also divided into groups based on certain defining characteristics, one of which is whether or not they lose their leaves in the fall in preparation for winter.
- Evergreen trees, also known as coniferous trees, are always green, meaning they retain their leaf material year round. Common examples of evergreens are the big pine trees that likely grow in the woods behind your home. Privacy hedges such as arborvitae and Leyland cypress are also evergreens and show the characteristic cone shape found in coniferous trees.
- Deciduous trees drop their leaves in fall. Examples of these in your landscape include: big, beautiful oak trees, the sweetgums that drop those prickly little seed balls, and the crepe myrtles that turn into spindly looking stalks when the leaves drop. Generally, these trees don’t exhibit that cone-like growth habit.
Why Do Deciduous Trees Drop Their Leaves?
Deciduous trees intentionally drop their leaves in the fall to conserve energy during winter. While plants can’t think in the same way we can, deciduous trees are very intelligent, biologically. When leaves grow in the spring, they include a special joint where they meet the branch from which they grow.
As fall sets in, days get shorter and temperatures get cooler. This sets a process in motion that starts by reducing the chlorophyll that makes the leaves green. Less chlorophyll means other chemicals present in the leaves become more prominent, making them appear red, orange, or yellow. In the background, other processes eventually weaken that specialized joint to the point where the leaves can be swept away with the wind.
Our bermuda and zoysia grasses embrace the same idea when they go dormant in the winter. While they don’t necessarily drop leaves like a deciduous tree does, they stop producing new leaves during the winter, placing focus on energy conservation and storage until spring weather arrives.
Is It Necessary to Remove Fallen Leaves?
Removing the leaves that fall from your trees is important for the health of your lawn and keeps your yard on schedule for treatments. Matted leaf litter can smother dormant turf, making for inconsistent green-up and a spotty yard in the spring. If wet and decomposing, leaves become a great environment for the development of fungal infections, which can be challenging and frustrating for your yard.
Keeping your leaves cleaned up is also important to make sure lawn treatment applications can proceed as scheduled. A lawn covered in leaves isn’t treatable. Liquid treatments are best when applied to clean yards; this helps ensure uniformity. If treatment is applied to leaf litter, the products may never reach their intended target—or worse, be removed along with the fallen leaves. Even the application of dry products such as lime and fertilizer cover less consistently when applied to yards with leaf litter. Keeping your yard clean ensures that your lawn service professionals don’t have to reschedule an application, which keeps your yard on schedule for important applications such as fall pre-emergents.
Important Takeaways:
- Trees are separated and classified by their individual species, and they are also divided into groups based on certain defining characteristics, one of which is whether or not they lose their leaves in the fall in preparation for winter.
- Evergreen trees, also known as coniferous trees, are always green, meaning they retain their leaf material year round.
- Deciduous trees drop their leaves in fall.
- Deciduous trees intentionally drop their leaves in the fall to conserve energy during winter.
- Removing the leaves that fall from your trees is important for the health of your lawn and keeps your yard on schedule for treatments.
- Reach out to one of our trained and knowledgeable lawn service professionals at Nature’s Turf to advise on and treat your lawn in preparation for the winter.
