Most leaf drop of deciduous trees and shrubs occurs by mid-December. Some plants will start dropping leaves as early as the second week of November while others drop leaves later. But of course, much of that depends on the weather and tree health. If it's unusually cold early, leaf drop is early.
Starting in late summer, many species of deciduous plants, including trees and shrubs, turn brilliant colors and shed their leaves.
In autumn, with the cooler temperatures and shorter days, the production of one hormone called auxin reduces. This in turn puts a strain on the abscission layer and causes the bond between leaf and branch to weaken. Eventually, the strength of the join is weakened enough that the wind will blow the leaf away.
At the end of fall, most deciduous trees lose their leaves for the winter season. In fact, the word deciduous comes from the Latin word decidere, which means to fall down or off. There are, however, a handful of deciduous trees around these parts that have a tendency to keep their leaves past fall.
There are a few instances where trees hold onto some (or even most) of their leaves throughout at least part of the winter. Usually, this is because the abscission cells don't form before the weather turns from autumn into winter.
Across the country, October is the month for leaf color and drop! More exact dates are below. Of course, if there's unusual weather in your area, like an especially dry season or early fall, trees may lose leaves sooner or later. Because weather has such a large impact, these dates may vary.
Maples, birch, willow, oak, hickory, dogwood, and redbud are all deciduous trees that are known for losing their leaves during the winter.
Excessive leaf matter on your lawn going into winter is bad for several reasons. First, it will smother the grass and if not removed very soon in the spring it will inhibit growth. Second, it can promote the snow mold diseases. And finally, turf damage from critters (voles, mice) can be more extensive in the spring.
Around our area, the earliest blooming/leafing trees typically begin to leaf out around mid to late March, according to the USA National Phenology Network.
Rather than the tedious task of raking and bagging leaves and taking them to the landfill, the best way to reduce greenhouse gases and benefit your garden is to leave the leaves! Leaves create a natural mulch that helps to suppress weeds while fertilizing the soil as it breaks down.
Never shear a shrub in fall (or ever, actually, but that's another article) and leave major pruning or renovation for late winter/early spring, or immediately after bloom for spring-flowering shrubs.
To support plants through this season of transition, make sure they get adequate water until the ground freezes. This is especially important if the summer season has been hot and dry, and for newly planted trees, shrubs and perennials. In fall, plants do not need as much water as they may have needed in summer.
Winter is usually the best time.
Dormant pruning is usually done in late winter, six to 10 weeks before the average last frost in your area. You can prune shrubs at any time of year if it's necessary—for example, to remove broken branches or dead or diseased wood, or to remove growth that is obstructing a walkway.
In addition to Rhododendrons, some Azaleas, Holly, and Boxwood, there are many shrubs that keep their leaves year-round, blooms. These look fantastic, especially when paired with Viburnum and Winterberry Holly which may lose their leaves, but have persistent colorful berries for you to enjoy all winter!
Check the Roots
Inspecting the roots of your plant is a great way to tell if it's dead or dormant! If it's dead, those roots are going to be moldy, smelly, and gross. If it's dormant, the roots will be light in color, supple, and considerably less gross.
A living limb will reveal green under the bark and will be slightly damp. A dead limb will reveal brown dry material. Another way to check whether a plant is dead or just dormant, is to inspect its root system. If the roots are rotten or shriveled, the plant is most likely dead.
Autumn is also called fall season and the trees shed their leaves during the autumn. The trees shed their leaves and flowers inorder to survive the upcoming harsh cold winters.
Leaf Drop Lasts Five Months
This is the time frame that is most commonly associated with leaf drop season. During this time, most trees go dormant in preparation for winter. As they do, leaves will gradually fall off the tree.
So long as the roots and woody parts of the tree are intact, there's a very good chance that your leaf-troubled tree will produce a new and healthy round of foliage next spring. Sometimes, denuded trees even grow a second set of leaves the same season.
Experts say raking and removing leaves can be worse for your yard – and for the planet, too. Leaving at least some of the leaves in your yard can help fertilize your grass and other plants, provide shelter for animals and even reduce emissions from landfills.
Fallen leaves, as an additional physical layer of organic materials above ground, provide food, shelter, and nesting or bedding materials to a variety of wildlife, as well as overwintering protection for a number of insects, all of which work together to contribute to a healthy yard.
What are the benefits to not raking leaves? If leaves are left on the ground to decay, they will reintroduce vital nutrients back into the soil. This can help to create optimal growing conditions for our yard or gardens the following year. Decaying leaves also make great mulch!
Winter temperatures cause the production of auxin to slow down and this breaks the abscission layer, causing the leaves to detach from the trees. Losing leaves helps the tree to retain water during in the winter and means that it needs less energy to stay alive. The fallen leaves help to add nutrients to the soil.
So, why are evergreens — like conifers such as pines, firs, junipers and spruces — immune to seasonal leaf changes and shedding, while species of deciduous trees — like aspens, ash, birch, cherry, elm, oak, poplar and maple — aren't?