What Do Apricot Trees Look Like in Bloom?
Apricot trees (Prunus armeniaca) in full bloom add bursts of color to an otherwise dull late-winter or early-spring landscape. Learning the stages of apricot flowers and what each stage looks like will help you know when to apply stage-specific products. It also will help you identify a tree as an apricot. Apricot trees are hardy in U.S. Department of Agriculture plant hardiness zones 6 through 9.
Bud Appearance and Development
Flower buds begin to swell on apricot trees when those trees start to awaken from winter dormancy and before new leaves are on the trees. When you see the tiny buds along the branches get larger, that is the time to spray 1 gallon of dormant oil on each apricot tree for every 5-by-5-foot ground space the tree takes up. When the buds appear, they are the same color as the branches, but soon they swell to a stage in which their exterior is pink. This pink bud stage is when fungicides are applied if those products are needed. The final bud stage is the popcorn stage, when the swelling buds have a white exterior on their tip from the emerging petals. During the bud stages, a late-winter freeze during which the temperature reaches 24 degrees Fahrenheit or below kills about 10 percent of the buds. A temperature of 14 degrees Fahrenheit at the popcorn stage, however, kills about 90 percent of the buds, according to a Washington State University Extension website article.
Full bloom occurs when the five white petals of an apricot blossom open fully. During that stage, each tree should be covered in white blooms with only sparse foliage present. When the trees reach full bloom, they are more susceptible than previously to freezing weather, and a temperature at or below 22 degrees Fahrenheit can cause 90 percent of the flowers to die. While the flowers are open, avoid getting them wet when you water the trees. Keeping the flowers dry helps to prevent fungal infections in the blooms and later on the fruits.
After the blooms are pollinated, the petals fall off, leaving behind branches with little foliage and the pink-hued remains of the flowers' cores. The core bases grow as young apricot fruits develop. After the petals fall off, check your trees for aphids, powdery mildew and twig borer, and provide treatment if necessary. When the petals have fallen, the trees become slightly less cold-hardy. Damage to 90 percent of the remains of the flowers occurs at a temperature at or below 24 degrees Fahrenheit, and a temperature at or below 25 degrees Fahrenheit damages 90 percent of the young, green fruits exposed after the shucks fall off them.
Chill Hours and Bloom
Depending on their variety, apricot trees range from needing 600 to 900 chill hours annually. The chill hours accumulate every hour the temperature is between 32 and 45 degrees Fahrenheit. If a year's chill-hour requirement is at the high end of the range for a particular apricot variety, then those trees may have 80 percent of their flowers open fully at once. When a year's chill hours are low, then the amount of flowers that are open fully at the same time may drop to under 50 percent, according to University of California Integrated Pest Management Online.
- California Polytechnic State University, Urban Forest Ecosystems Institute: Apricot
- University of California, Fruit and Nut Research and Information Center: Apricot Flower Development
- University of California, Marin Master Gardeners: Growing in Your Garden Now -- Apricots
- University of California Integrated Pest Management Online: Apricot -- Why Is the Bloom Season Important in an IPM Program?