Rachael Boyle, Phillips-Rooks District Extension Agent Agriculture and Natural Resources

There have been a number of trees that have been slow to leaf out. In some cases, this is likely due to accumulated stress. We often think of plants reacting to stress that happened during the current season or possibly the previous year, but it may not be that simple.

This all may have started during the winter of 2017- 2018. Many areas of Kansas had virtually no rain or snow from November through most of April during that winter. This put plants under a tremendous amount of stress. Plants under stress often react by setting an abnormal number of fruit buds. This helps ensure the survival of the species even if the parent plant dies.

So lots of fruit buds were set during 2018. Those buds matured into flower and then fruit (seeds) during 2019. Think back to the summer of 2019. Certain plants bloomed very well that year. Maturing this much fruit takes a great deal of energy. This resulted in such low energy levels in the fall that the plants just didn’t have enough energy to make it through the winter or may have delayed leaf out.

Areas with too much rain last summer had that additional stress added to the mix. Roots need oxygen as well as water and too much rain can damage root systems. We also had a sharp drop in temperature during the fall of 2019 placing trees under even more stress. Some trees lost branches during the summer of 2020 and others died, but many trees were under stress. Then we had the extreme cold in February of this year. Trees that were weakened have been slow to leaf out with some losing branches.

So what do we do? The only thing we can do now is try to avoid any further stress. That means watering during dry weather. Don’t overdo it as too much moisture can damage root systems. The goal is to keep the soil moist but not waterlogged while allowing the top of the soil surface to dry between watering.