The season of bloom continues in Washington State with apple trees waking from dormancy to produce flowers that attract bees and eventually become the crisp and juicy apples that we will harvest come fall. In fact, our family and hometown of Wenatchee spent time celebrating the apple blossom season by gathering for the Stemilt Grand Parade last weekend during the annual Washington State Apple Blossom Festival. (In case you were curious, that’s my brother, West, getting ready to drive the parade route along with other members of the Mathison family in a 1967 VW bug that was recently restored to look like Stemilt’s mascot – a ladybug.).
In this post, I thought I would share more scenes from the beauty that is apple blossom, and explain to you what happens in the orchard during this important time of the year.
In Washington State, full bloom for apple trees typically occurs from April 22 to May 8. The first flowers can appear on trees in early April. The latitude of the orchard and the apple variety dictate when a particular tree blooms. Apple blossom occurs in our southern growing locales like Pasco and Mattawa first before moving north to areas like Lake Chelan and Stemilt Hill. One of the facts I’ve always found fascinating is that the Cripps Pink cultivar of apples (which produces Pink Lady brand apples) is the first variety to bloom but the last to harvest!
The apple blossoms themselves are white and can have a noticeable white pink tinge (like the Gala variety pictured below). The buds that eventually become blossoms actually develop on trees during harvest the prior fall. They become visible after leaves drop from trees in the late fall, and must endure the cold weather during the winter in order to have a chance of blooming come spring.
Once trees come out of winter dormancy, the buds begin to swell and slowly open. A branch of a tree produces a cluster of six blossoms when it blooms, and the center blossom, called the king bloom, is the first to open. Apples that grow from a king bloom are often larger than those around them, and many growers will thin the smaller apples growing nearby in the summertime in order to make room for the king bloom apple to grow to its potential.
In order for an apple blossom to develop into new apples, they need to be pollinated. For the most part, apple trees require two sources for pollination. Growers plant pollenizer trees or graft limbs of a pollenizer on trees nearby the trees they want to produce a crop from. Crabapples are commonly used as pollenizers, but compatible varieties for that particular tree also work well. Bees are the second, and most important, part of pollination. As you see in the photo below, growers place rented beehives in their orchards when blossoms are just starting to open. The hives remain until bloom passes.
From there, the bees get to work! They visit the pollenizer tree and then the apple tree, transferring pollen from the anthers of a flower to the stigma of the same or another flower in order to pollinate (or fertilize) the blossoms. Bees may visit blossoms multiple times in order to deliver the amount of pollen needed for successful pollination. Check out the bee below helping produce a future apple!
If all goes according to plan, the blossoms are pollinated and new apples officially set on the tree and begin to grow. Of course, there are many obstacles that can get in the way of bloom and pollination. In Washington State, frost is a big threat to apple blossoms. Growers have a few tactics to protect their crops from frost, including wind machines and overhead irrigation. They closely monitor temperatures to determine if and when they need to deploy a frost protection tactic.
Wind machines draw down warmer air and blow it into the orchard, which helps prevent stagnant cold air pockets from sitting at the tree level and killing the blossoms. Overhead sprinklers may be turned on for frost protection to apply water to the buds. The water acts as an insulator on buds in order to keep them at or above 32° F (and keep them alive!). Aside from frost, bees don’t like to fly in cold, wet, or windy weather so growers hope for good weather when their apple trees are in bloom.
As the flowers on apple trees fall from the tree, leaves appear, and a new apple begins to take shape and grow on the tree. Before we know it, the time will come to harvest a new crop of delicious and crisp Stemilt apples!