Why Evergreens Stay Green in Winter

Why Evergreens Stay Green in Winter

March 7, 2022  |  Evergreens, Garden, Winter
Evergreens tree branch

Evergreens are one of the most beautiful parts of any yard or garden. 


Commonly associated with winter, Evergreens get their name from their unique ability to retain green leaves in the winter season.  


Other trees lose their leaves and go into a dormant rest during late autumn and winter, but the evergreen stays awake and active all year long.  


As a result, the deep greens of pines, hemlocks, spruces, and cedars add a splash of color to an otherwise white and gray winter landscape.  


In this post, we will explain why Evergreens retain their leaves all year and why other trees do not. 


Green Ever After 


There are two types of trees.  


First, and most commonly, is the Deciduous tree. Deciduous trees are trees like oaks and maples, they have large, flat leaves that grow in spring, are a vibrant green in summer, and succumb to oranges and browns in autumn before they finally fall to the ground.  


Second, is the Coniferous tree (colloquially known as the evergreen). Unlike Deciduous trees, Coniferous trees’ leaves are dark green waxy needles. Coniferous trees retain their waxy needles year-round and remain active during the winter.  


But why do Deciduous trees lose their leaves, and more importantly, why do coniferous trees retain theirs? 


The answer has to do entirely with photosynthesis.  


In the fall and winter, the Earth receives less direct sunlight due to its tilted axis. Because there is less energy from the Sun, photosynthesis is less effective.  


In warmer climates, deciduous trees respond accordingly, shedding their leaves and sealing off their waterways in favor of a dormant state. This preserves the tree’s life and allows it to start photosynthesis anew in the coming spring.  


Coniferous Evergreens employ a different strategy. Since they are usually found in colder climates, coniferous trees produce their leaves in the form of a tightly rolled, waxy needle. The Coniferous needle is much more effective at retaining water as compared to the flat, thin surface of the deciduous leaf.  


As a result of their shape and waxy coating, the Coniferous tree can keep their leaves during the winter and continue the process of photosynthesis undeterred by the cold.  


Because they continue photosynthesis into the winter, Coniferous trees retain their green chlorophyll (the green pigment responsible for photosynthesis) all year round.  


Needle Shedding 


Because Coniferous trees remain active during the winter, many people assume that they never shed their needles.  


If you have an evergreen in your yard or garden, then you know this simply isn’t true. 


Coniferous trees do shed their needles regularly to ensure that the tree can perform photosynthesis with maximum efficiency.  


Needle shedding often occurs in early spring, and new needles grow in spring and summer. 


Discarded needles can help contribute to a healthy forest floor, but in your garden, needles can get in the way of other plants’ growth, so it is best to collect excess fallen needles.  


Newer needles are found near the tips of branches, while older needles tend to appear higher up.  


Needles typically last 2-4 years, and one-third to one-fourth of needles are shed each year.  


If you notice more needles have been shed than usual, or your Evergreen is losing the tips of its branches, this is a sign of tree illness, most commonly caused by disease or infestation.  


If your evergreen is showing signs of illness, it is time to contact your tree health specialist.  


Green in a Weary Winter 


Many homeowners and gardeners in Ohio prefer Coniferous trees in their yard as they add an infusion of green to our gray winters.  


However, while evergreens stay green year-round, they do not show the vivid reds and oranges that deciduous trees display in the fall.  


Planting new trees in your yard is never an easy decision. When it’s time to plant a new tree and start a new chapter in your garden, Knollwood Garden Center is the place to go.  


Knollwood's Nursery department strives to offer the most beautiful trees and shrubs to create the backbone of your landscape and gardens. 


Stop by Knollwood Garden Center today!