As daylight lengthens in the spring and temperatures rise, trees start to break dormancy.
While winter is still hammering Grandpa’s Orchard in Michigan, spring is starting to come to southern areas, and many are likely to see their fruit trees starting to break dormancy.
As daylight lengthens in February and March, fruit trees start to sense the change. Most importantly they sense warmer temperatures. Some of this is caused by more sunlight being absorbed by the tree as the days lengthen, but more of it is just because temperatures start to rise because more solar energy is available to warm the air and soil.
Regardless of where you live, eventually all trees will break dormancy. It usually starts very gradually with some small signs that you might see if you look real close, and then if the weather cooperates will progress to blossoms and leaves emerging fairly rapidly. However, sometimes warm periods will start fruit trees breaking dormancy, and then cold temperatures will come along and put it to a halt. If temperatures get too cold, then buds and trees can possibly be damaged. In general as fruit trees start to lose dormancy, you can often see a visible brightening of last year’s new growth.
Sweet and tart cherry tends to be one of the first major fruits to visibly show signs. The blossom and leaf buds will start to swell and get fatter. Leaf buds will be “pointier” while blossom buds tend to be fatter and blunter. As time goes on you will start to see some green in the leaf buds. When blossom buds start to show some white, then blossom time isn’t far off. Pray for no freeze!
Apricots, plums and prunes will ordinarily be right there along with the cherries. Fairly similar signs, but as apricot flower buds swell they tend to be a pinker color. Plum flowers buds are almost always white.
Peaches and nectarines will follow closely behind. Flower buds will start to get nice and fat and as they get closer to opening, more red. On peaches and nectarines, there are two types of bloom— “showy” which is usually bright pink and attractive, and “non-showy” which is a darker, subdued pink and not as attractive. This is a genetic trait, and doesn’t seem to have much relationship to hardiness or other traits.
Pears should be next in line usually. There isn’t as great deal of difference between the early blooming pears and later blooming pears, as there is with apples.
Apples are almost always the last fruits to bloom, and there can be quite a difference between when the early bloomers open and the late bloomers. That is why it is important to pay some attention to early-midseason-late bloomers when planting your backyard orchard— especially if you have just a few varieties. You want to make sure that there is another pollinator variety blooming and overlapping the other ones.
In the spring, there is very little you can do to delay breaking dormancy. Mother Nature seems to have the upper hand and can defeat almost any attempt. So, expect early springs, late springs, and “normal” springs— whatever they are. About the only way to slow down fruit tree development in many areas is to try to maintain a snow cover as long as possible, and in the spring encourage cooler temperatures of the wood by misting or spraying the tree with sprinklers. However, this can lead to other severe problems too, so Grandpa thinks it is best to just sit back and watch Mother Nature do her job!