Pollination is the biological process where pollen is transferred from the male part of a flower (the anther) to the female part (the stigma). This transfer leads to the fertilization of the flower’s ovules, which is necessary for the flower to develop into fruit. Without successful fertilization, the apricot flower will wither and fall off the tree, preventing fruit from forming.
Understanding Apricot Self-Pollination
The majority of apricot varieties are considered self-fruitful, meaning they do not require a separate pollinator tree to set fruit. A self-fruitful tree can fertilize its own flowers using its own pollen. This occurs when pollen from the anther of one flower is transferred to the sticky stigma of the pistil on the same tree.
This genetic characteristic, known as self-compatibility, benefits growers who can only accommodate a single tree. Varieties such as ‘Chinese’ (or ‘Mormon’), ‘Harcot,’ and ‘Blenheim’ are reliably self-fertile. Even with self-compatible trees, the presence of another apricot variety nearby often increases the total yield and leads to a more dependable harvest.
Exceptions to Self-Fertility
While most varieties are self-fruitful, a minority of apricot cultivars are self-unfruitful and require cross-pollination. These trees are incapable of successfully fertilizing their flowers with their own pollen due to self-incompatibility. The pollen may germinate on the stigma, but the growth of the pollen tube is arrested before fertilization can take place.
Cultivars such as ‘Goldrich’ and ‘Perfection,’ along with certain older European types, fall into this category. For these trees to produce fruit, a suitable pollinizer—a different apricot variety that blooms simultaneously—must be planted within approximately 50 feet. This proximity ensures insects can easily carry pollen between the trees, enabling successful fertilization.
Ensuring Successful Fruit Set
Although many apricots can self-pollinate, the physical movement of pollen relies almost entirely on external factors, as the flowers are not structured for wind pollination. Apricot flowers, which bloom early in the spring, must be visited by insects like honeybees and bumble bees. The absence of these insect pollinators, even for a self-fertile tree, will result in a complete lack of fruit set.
Weather conditions during the bloom period are the greatest threat to a successful apricot harvest. Apricot blossoms are sensitive to cold temperatures, and late frosts can damage or kill the delicate flower parts, preventing fertilization. Even if temperatures remain above freezing, cold, rainy, or windy weather severely reduces the activity of pollinating insects. Honeybees, for example, do not fly effectively below 55°F (13°C). This leaves the flowers unpollinated during their short window of receptivity, which lasts only about 24 to 48 hours.
Manual Pollination Assistance
Home growers can manually assist the process if weather conditions are poor or natural pollinators are scarce. This technique involves using a small, soft artist’s brush, a cotton swab, or a gloved fingertip to transfer pollen. The grower gently dabs the brush into the center of a fully opened flower to collect the pollen grains from the anthers.
The collected pollen is then lightly brushed onto the sticky, central tip of the pistil (the stigma) of the same flower or a different flower on the tree. Performing this manual pollination during the warmest, driest part of the day, when the flowers are most receptive, can significantly boost the chances of a successful fruit set.