“Bud Break” – What is it, and what causes it?
“Rough winds do shake the darling buds of May…” (William Shakespeare)
Whether the buds on your tree are shaking in April or May doesn’t much matter. What does matter, is that a fascinating process goes into the buds being there at all.
In the winter time, in the Midwest, trees (except conifer trees) go dormant. This means they shed their leaves, and burn very little energy to stay alive. Water, which is typically frozen, is unavailable in the winter, and trees actually stop growing.
The buds which become visible as warmer temperatures move in were actually formed the previous summer, but spent the winter protected by thick scales.
In order for the tree’s buds to start to break, the tree has to go through a colder period. Then, as warmer temperatures move in, the tree “knows” that it is time to let the buds out, and start creating shoots and leaves.
If we have a particularly warm spell, say in December, why don’t the trees start to break buds then?
Well, trees are programmed to wait for the right time to do so. If a tree breaks buds in December, the scales peel back from the buds leaving them susceptible to the coming cold. If that happens, the colder temperatures in January would freeze the buds, and the tree wouldn’t experience any growing in the following summer.
So they wait. And when the time is right, they break buds and begin their growth period. In Missouri and Kansas, our trees are beginning bud break right now. Get out there and marvel at the fascinating process which allows trees to grow each year. Have a fabulous spring!