There are four main phases of peach tree development: the dormant phase, the flowering phase, the fruit phase and the harvest. Each of these phases have additional stages of development.
In the dormant stage, two types of buds are visible on peach trees. Single vegetative buds are small, while the flower buds are larger, rounder and hairy. In this stage the buds are not visibly swollen. The first period of dormancy is a chilling period in which chemical reactions occur that allow the tree to grow. A second dormancy period is the time the tree remains in dormancy after meeting chilling requirements.
Swollen Bud or Bud Swell
The flower initiation stage begins with the bud swell. In this stage, peach trees stop producing vegetative tissue and start producing flowers. In this stage swollen buds are noticeable but no green tissue is apparent.
Following the flower initiation stage is the beginning of the flower bud differentiation stage. The bud-burst stage is referred to as the “green calyx” or green bud stage. The sides and tops of the swollen buds are noticeably green.
Quarter or Half-Inch Grown
The quarter and half inch stage of peach tree development refers to the amount of leaf tissue visibly coming out of the leaf buds. This is also called the “calyx red” stage.
In the final steps of the flower differentiation stage, or in the pink stage, the flower reproductive parts develop. As the buds continue to open, the red petals or corolla can be seen.
The bloom stage signals the end of the flower differentiation stage and is the beginning of the anthesis stage, where the flowers open and bloom. First bloom refers to the time when the flowers first begin to bloom. Full bloom indicates the time when most of the flowers are open. During this stage the flowers that are pollinated and fertilized will begin the fruit development stages.
Post bloom and after pollination and fertilization, the petals of the peach blossoms drop or fall off of the tree. This stage is also called “shucks on” or “in the shuck.”
Over approximately the next 50 days, rapid cell division occurs in the fleshy parts of the fruit. In addition, the seed grows up to its maximum length. As this growth occurs, the shuck is split by the developing fruit. As the fruit grows, the shucks will eventually fall off. This is called the initial fruit swell or stage one of fruit development.
Stage Two Pit hardening
Stage two of the fruit development is mostly internal. The fruit doesn’t change much. Internally, the pit hardens. The embryo within develops a shoot, a primary root and two leaves. This stage can be relatively short for early peach tree varieties, or last up to two months for late cultivars.
Stage III Final Fruit Swell
A second fruit swell in stage three of peach tree fruit development is the final six weeks before harvest. The fruit size grows rapidly and may account for up to 40 percent of the final fruit size.
The first harvest refers to the first picking of the ripe peaches. As the remaining fruits ripen, further pickings make up the general harvesting phase.