If you live in the DC and Baltimore region, you are well aware of the huge range of seasons we get. Summers often bring blazing heat, Fall explodes with color, winters bring crisp air and snowflakes and are followed by a vibrant, blooming Spring.

Many adore the changes in the seasons, while others take a while to acclimate. If you are one who struggles with the low temps each winter, you may be inspired by your tree neighbors who can brilliantly withstand them time and time again. 

(*non-readers who still want to learn, scroll to the bottom and watch the short video;) 

Dormancy is the name of the game. Our region is filled with perennials that have mastered this method, going into a plant-style hibernation each winter. Sometimes during the process, certain plants almost appear dead. But we know there is a tedious survival strategy going on beneath the bare appearance of each tree, especially during December – February. Essentially, dormancy is the plant’s way of halting its work and energy usage in order to preserve its own life during the cold.

At Blythewood Farm, we are able to watch our very own Horse Chestnut tree up close as it preserves, conserves and sustains itself each year through the process of going into dormancy. Each winter, she goes bare, and prevails in the Spring. 

This is the mission for all different types of perennial plants each year as they must enter a state of zero or minimal activity in order to survive. For trees, it is primarily deciduous trees such as maples, oaks and ash trees. Each plant that goes dormant greatly slows down its metabolism, energy consumption and growth. 

When does this process begin? You guessed it ~ the falling of leaves! As you’d expect, fragile leaves would become frozen through the cold. Preserving them would require too much energy from the tree that must be saved for its internal system. The first step towards dormancy is letting them go, so that the tree may reserve energy for its roots and cell system. What actually causes the leaves to fall? A substance called abscisic acid is sent out from the trunk and scares them away. At this point, the season is simultaneously changing and the temps are dropping.

You may be sad to watch the bright colors fall away, or to watch the Blythewood crews blow them away. If so, click here to read more about what causes the changing colors in leaves.

Once the winter months are underway and leaves have fallen, each tree is prepared to maintain only its most essential systems and achieve the overlying goal through the winter: keep the living cells alive. 

Although some cells will die or will have already been dead, they can still be useful towards preserving the rest of the tree’s system, by taking the hit on freezing liquid.

 

This is where there tree begins to go a little insane in the membrane . . . 

 

Each winter, deciduous trees impressively transform their cell membranes so that they become more pliable. This stage is sometimes called the “glass phase” as the cell membrane transitions into a durable, non-liquid texture that can withstand its surroundings. This change allows the water within the tree to freeze throughout the gaps between the cells rather than inside of the cells, killing them. 

Another way trees are able to transform their cells is by sweetening the fluids within their living cells. They convert starch to natural sugars which lowers the freezing point inside the cells. This also helps the cells become more pliable and able to withstand the frozen liquid surrounding them. 

This method prevails through the winter months until temperatures steadily rise at the end of February/beginning of March. The tree will then return to its regular processes, allowing the cells to hold liquid once again and get back to generating energy and growth.

Read about dormancy for vines at UMD Extension.

Or click here for more info on how perennials survive the winter!