Apricot trees (Prunus armeniaca) are popular home orchard fruit known for their early spring bloom. The successful development of their sweet, fuzzy fruit depends entirely on pollination. This process involves the transfer of pollen from the male part of a flower to the female part, which determines whether a tree will bear fruit. Understanding this mechanism and the specific needs of the variety you plant answers whether a single tree can produce a harvest.
Apricot Pollination Requirements
The answer to whether a second tree is needed depends on the apricot variety’s pollination classification. Apricot cultivars are divided into two main groups: self-fertile and cross-pollinating. Most modern apricots are self-fertile, meaning a single tree can produce a crop without a partner.
Self-fertile varieties, such as ‘Moorpark’ and ‘Blenheim,’ possess the capability to fertilize their own flowers. While they do not strictly require a second tree, planting a genetically distinct variety nearby often increases the overall fruit set and yield.
The second classification is cross-pollinating, or self-unfruitful, which includes some older heirloom cultivars. These trees possess a genetic barrier that prevents their own pollen from successfully fertilizing the flower. For these exceptions, a second, compatible apricot tree that flowers at the same time is necessary to ensure fruit production. Always consult the nursery tag for the specific pollination requirement.
Understanding Apricot Flower Biology
Apricot flowers are hermaphroditic, meaning each blossom contains both male and female reproductive organs. The male parts are the stamens, where pollen grains are produced. The female part, the pistil, includes the ovary and the receptive tip called the stigma.
For fertilization to occur, pollen must be transferred from the stamen to the stigma, a process mediated by insects. Apricots are not wind-pollinated; they rely on bees, flies, and other early spring insects to carry the pollen. Insects are attracted to the nectar and inadvertently pick up pollen before depositing it on the sticky stigma of the next flower they visit.
Once the pollen lands on the stigma, it must germinate and grow a pollen tube to reach and fertilize the ovule within the ovary. The duration that the stigma remains receptive is known as the effective pollination period (EPP). If pollen transfer or tube growth is delayed by cold temperatures, the EPP can expire before fertilization is completed, leading to flower drop.
Ensuring Successful Fruit Set
A tree can have the correct pollination partner and still fail to set fruit due to environmental or maintenance factors. Apricots are among the first fruit trees to bloom, making them highly susceptible to late spring frosts. Temperatures below 28°F can kill the open blossoms, resulting in a complete loss of the potential crop.
The tree must first satisfy its required chill hours, the cumulative period of cold temperatures (typically 35°F to 45°F) needed to break winter dormancy. Most standard apricot varieties require 600 to 900 chill hours. Insufficient chilling leads to sparse, delayed, or weak blooming, preventing the tree from transitioning to reproductive readiness.
Another factor preventing fruit set is poor pollinator activity during the short bloom window. Apricots often flower when the weather is still cool, and bees are less active in cold, windy, or rainy conditions. Even a self-fertile tree will fail to produce fruit if insects are not flying to move the pollen.
Proper tree maintenance also influences fruit development. Apricot fruit develops primarily on short, two-to-three-year-old spurs. Strategic pruning is necessary to encourage the development of these fruiting spurs and ensure sunlight reaches the interior of the canopy. Without adequate light and pruning, the tree’s energy may be misdirected toward excessive foliage rather than flower bud production.