In late summer, the final peaches are harvested and the tree refocuses its energy on new twig and leaf formation. On these new shoots, “bud set” begins to occur. The tree begins to create buds that will overwinter and then become next year’s fruit and leaves. All of next year’s growth is pre-determined within the tiny buds. If you look at a bud under a microscope, you will see every part of the flower pristinely formed, ready to simply elongate when weather conditions permit and the spring flush is initiated. In stone fruits, the buds are set into two categories; “leaf buds” will become next year’s leaves, while “fruit buds” trans- form into flowers and subsequently fruit.
Next, October-November rolls around and day length decreases. The changing “photoperiod” triggers the tree hormones to prepare for winter. Photosynthesis ceases and sugars that were made in the leaves are relocated to the tree’s trunk and roots. The tree then loses its leaves, but buds remain on the branches as they contain all of next year’s growth.
At this point, energy flow within the tree does not cease, but it does transform. Without leaves the tree cannot actively create energy, so growth becomes reliant on stored energy. Energy that was produced from photosynthesis was stored by the tree in sugar molecules. At the current time of year, these stored sugars are broken apart to drive metabolic processes. Due to our mild winters, energy is flowing through the tree all year around, even when we cannot see it.
We now wait out the tree “dormancy”, until late winter when we will see “bud break.” At this time, cells within the buds will elongate to form leaves, flowers, and finally, fruit. We will learn about the next steps of this process when bud break draws near. But remember: all of the beautiful lush green spring growth is already contained within the existing buds.
