When Do Peaches Flower?

Like other fruits, peaches start as flowers on their trees. The blooms of peach trees (Prunus persica, which grow in United States Department of Agriculture plant hardiness zones 5 though 9) appear three to five months before the fruits, but the exact time the trees flower depends on the previous winter's temperatures and the trees' variety.

However, all too often, gardeners will run into an issue and say "my peach tree didn't bloom." There are some easy ways to identify the issue, and ensure that peach tree flower buds grow strong.

Chill Hours' Effect

Peach trees typically bloom in spring. Whether flowering occurs early or late in spring depends on winter's weather and the trees' chill hours requirements. During winter, peach trees accumulate chill hours, which are the number of hours when the temperature is no higher than 45 degrees Fahrenheit.

When the trees reach the required number of chill hours for their variety, the next warm spell causes them to produce flower buds. The fewer chill hours a peach tree needs, the sooner it produces flower buds in spring. Most peach tree varieties need 600 to 900 chill hours. If your peach trees do not receive enough chill hours, their flowers may not open or they may have only a few flowers that open.

Cold Damage

Picking a peach tree variety that has chill hour requirements slightly below the number of chill hours your area receives is important to prevent damage to the trees and their developing flower buds. If your peach trees have enough chill hours and "wake up" during a warm spell at the end of winter, the flower buds they produce could be damaged by late-winter freezes.

Each stage of flower development is increasingly more susceptible to subfreezing temperatures. Swelling buds are the most resilient. The temperature has to be at or below 1 degree Fahrenheit to kill 90 percent of swelling buds on peach trees, but 90 percent of post-bloom flowers are killed by a temperature colder than 25 degrees Fahrenheit.

Stages of Development

The flowering stages of peach trees are the same as the flowering stages of other stone fruit trees. Tiny, dormant flower buds can be seen on branches in winter. Once the trees awaken in a warm spell, the buds begin to swell and darken to pink. After that, the first flowers open, but most of the buds remain closed until the full bloom stage, when each entire tree is covered in open flowers.

Shortly after pollination and fruit set, the flower petals drop off the flowers. Knowing these stages is important for properly applying fungicides and insecticides to the trees to prevent diseases and other problems without affecting fruit quality.

Peach Tree Flower Bud Chores 

When flowers and foliage emerge on your peach trees, it is time to fertilize the trees. A 3- to 4-pound per year of tree age dose of ammonium sulfate around each tree provides all the fertilizer needed for the rest of the year. When the trees' flower buds reach the closed, pink stage in rainy springs, apply fixed copper, Bordeaux or chlorothalonil to the trees to prevent shot hole fungus and brown rot.