The apple tree is a deciduous, flowering fruit tree that grows from seed. Though these trees require full sunlight and warm temperatures to fully thrive and produce, the apple tree's life cycle is dependent upon the four seasons and their varying climates.
The apple tree begins its growing season during early spring. At this time, the tree begins sprout new branches and foliage. As the foliage grows, buds and shoots begin to form. The buds bloom, producing flowers. The stamen of the flowers produces pollen, which rests within the flower until it is released for pollination. The pollination process is primarily completed through pollinators such as bees and insects that feed off the flower's nectar. As the pollinators feed, the pollen of the flower attaches to them and is transferred to the stigma of the flowers as the pollinators pass from flower to flower. As the pollination process is completed, the flowers' ovules are fertilized with the pollen and the apple tree's seed production begins.
The apple tree enters the summer months in full bloom. As the fertilized flowers produce seeds, the petals of the flowers begin to fall and the fertilized ovaries begin to develop into apples. The innermost part of the ovary develops first, creating the apple's core. The outer wall of the ovary develops into the edible part of the apple. The fruit gradually grows larger and the color of the apples begins changing to its full color, whether red, green or yellowish red. During this process, the tree also begins to produce new growth for the next growing period.
As the fall season approaches, the apple tree prepares the apples for harvesting. The apples become fully ripe with complete color. If the tree is not harvested, the apples will become too heavy for the branches and will begin to drop. As the temperatures begin to decrease, the tree's chlorophyll production will also decrease. The leaves will change colors and the tree will begin to naturally shed its old and weak branches and stems. The tree will grow little, if any, during this season as it adjusts to the cooler temperatures and prepares for dormancy.
The apple tree will stay dormant during the winter months. It will not grow or bloom. However, bouts of warmer temperatures during the winter may bring forth small areas of new growth. The new growth will die back as the temperatures plunge again.
When raising an apple tree, consider the seasons as you develop its care schedule. Fertilize the apple tree before and after the growing season, ideally in early spring and late fall. Promote vigorous growth by pruning branches and stems, watering regularly and providing good drainage.