It’s a brisk, early November morning. The weather is cool and your yard is as colorful as its ever been. It won’t be long before the final leaves have fallen as we close in on winter.
If you take close note of the trees in your yard, you may see a trend. While many maples, hickories, and fruit trees are dropping leaves like crazy, some trees or plants in your gardens and yard still hang on tight to their leaves – specifically oaks, beech, witch hazel, hornbeams, and willows.
As the fall passes and we head into winter, those trees still have their leaves. Some drop but many weather the elements and manage to hang on until spring, and then detach. The effect is called Marcescence – and this is a characteristic demonstrated in young plants, and sexually immature branches on certain plants. It is a behavior in deciduous trees, and some call these trees “everciduous” when they manifest this characteristic. On a brisk winter day, when all the other leaves have fallen, these plants provide a little bit of softness, sound, and color to an otherwise drab landscape.
When plants begin to enter winter dormancy, the cells at the petiole at each leaf begin to form an abscission layer. That process cuts off the flow of nutrients and fluids between the leaf and the branch. When chlorophyll is no longer present in the leaf (which makes the leaf green), the true color of the leaf shows. Ultimately the abscission cells complete their job, resulting in a cellular barrier between the stem of the leaf (petiole) and the branch, causing detachment of the leaf.
This appears to be a protective adaptation for trees to carry their leaves through winter to spring. It’s not certain the primary cause, but some of the theories are listed below
- To help protect the branch and buds from getting freeze-dried in the winter by protecting the branch in part from the winter elements.
- To provide a fresh layer of leaf litter in the spring, which serves as a source of organic nutrients and soil richness.
- To discourage browsing herbivores (deer, rabbits, etc.) from eating young, tender branches containing buds.. Dry, crunchy leaves hanging on these branches may make it less desirable to a hungry animal, and the rustling may make the herbivore prone to predators.
Marcescent plants and evergreens offer something for your garden that few other plants can. When the deciduous plants have shed their leaves and are down to bare stems and branches, these plants bring some color, texture, interest and much needed focal points to your garden beds and yard when everything else is bleak. So consider their marescent characteristics another helpful design element when thinking about your landscape layout through the seasons.
Chesapeake Landscapes provides full-service landscape and hardscape design and installation throughout Harford, Baltimore, and Cecil Counties. Schedule an appointment with a designer here!