Apple trees typically bloom in the Springtime. So, you may ask yourself, why is my apple tree blooming in September? Usually, this happens due to the warm Fall weather and an unusual amount of sunlight. Such conditions can cause out of season blooming, as the tree is still receiving photosynthetic light in abundance. Furthermore, some varieties of apples will naturally bloom late, such as peach-leaf crabapples, which are typically some of the last apple varieties to blossom every season.
In addition, if your apple tree has recently been replanted, or subjected to a “reset” in terms of its growth, it may respond by blooming outside of its typical season. Finally, if the tree is heavily fertilised, this can also disrupt the seasonal blooms. Each of these scenarios can cause your apple tree to produce flowers and fruit in September, when such behaviour would typically be considered unusual.
Insects and their Impact on Apple Trees
In some cases, insects can also play a role in your apple tree’s late blooming. Cicadas are well known for their tendency to hide behind tree bark, which can lead to them being inadvertently covered by new growth. As the weather begins to warm, cicadas can emerge from beneath the bark, and this can cause the apple tree to flower earlier in the season due to the disturbance.
Not only can Apple trees be affected by insects but their blooming cycle can be affected by other environmental stresses such as drought, disease, and artificial lighting. Droughts can cause a tree to become stressed which leads them to try and grow new blooms in order to survive. Similarly, if an apple tree is infected with an airborne disease, such as powdery mildew, the tree may respond by busy blooming in order to increase its chance of survival.
On the other hand, artificial lighting can affect the biological clock of an apple tree, especially if it is exposed to light for a prolonged period of time. This is because the tree’s circadian rhythm is reset and the internal clock of the tree mistakenly signals it to begin flowering and producing fruit earlier in the season.
Temperature and Humidity
In addition to insects and environmental factors, temperature and humidity can also play a role in your apple tree blooming during September. Generally, a decrease in temperature below 18°C will cause a tree to bloom earlier than it would normally. Conversely, a high concentration of humidity present, can also have a similar effect on a tree’s cycle. Both of these conditions can lead to the apple tree displaying an unusual blooming pattern.
Furthermore, the location of your apple tree is also an important factor to consider when asking why it’s blooming in September. If the tree is close to a body of water, such as a lake or stream, then higher levels of humidity may affect its seasonal blooming. Additionally, the soil composition of the tree’s location can also play a role. If the soil contains a high amount of clay, then water can become trapped which can lead to higher overall levels of humidity in the area.
Finally, a sprout-producing hormone known as gibberellin, can also have an effect on when your apple tree blooms. Gibberellin is a natural plant hormone produced by trees and can affect the blooming process depending on the season. If the Apple tree has been exposed to an abundance of this hormone, it could blossom early.
Weather Variables
Weather variables such as wind, rainfall, and sunlight can also impact the blooming cycle of an apple tree. For example, wind can damage the flowers and buds, leading the tree to replace them with new blooms earlier in the season. Furthermore, a good amount of rainfall can give the tree an artificial cooling effect as it needs less energy to hydrate itself. Finally, if the tree is receiving an unusual amount of sunlight, then it will not realise that the season has changed and may continue to blossom.
Apple trees can also experience varying levels of stress during the year which can affect their flowering behaviour. For example, exposure to pesticides or extended periods of drought can lead to an Apple tree blooming outside of its regular cycle. Additionally, pruning and rejuvenation of older apple trees can also cause them to bloom later than normal.
Air pollution, in the form of nitrogen compounds or ozone, can also be an issue for certain trees. Although it can be hard to predict the exact effects of air pollution, the presence of these elements in the atmosphere can reduce the amount of light available for photosynthesis and can even stunt the growth of certain plants. As a result, such exposure can have a significant effect on an apple tree’s regular blooming cycle.
Soil Variables
Soil variables such as moisture and compaction can also impact an apple tree’s season. If the soil is overly dry then the tree may need to expend a lot of energy in order to grow, which can delay its blooming cycle. Similarly, if the soil is heavily compacted, then oxygen and other essential nutrients may be blocked from the root system, leading to stunted growth. Such conditions can cause a tree to flower later in the year, particularly if it is already in a weakened state due to other environmental factors.
Finally, if the soil is overly acidic, it can prevent the roots from accessing essential nutrients, leading to a decline in growth and blooming. Likewise, a deficiency of phosphorus or nitrogen can cause a tree to flower later. Both of these situations need to be addressed in order to ensure healthy growth and blooming of your apple tree.
