For many perennial fruit crops, we can use shoot growth as an indicator of overall plant energy and vigor. It is common for shoot growth to slow down, and sometimes even stop completely, setting a terminal bud, during the fruit fill period.
When this occurs, it is an indicator that the plant is not producing enough photosynthetic energy to both fill fruit and develop growth, so it will sacrifice the new growth to be able to reproduce.
When we manage plant nutrition to optimize photosynthesis, it is possible to restart healthy new shoot growth, without the addition of nitrogen.
On these apple trees in Michigan, the trees set terminal buds on new growth tips in late June, during early fruit fill. We started working with this block this year and recommended foliar nutrient applications designed to increase photosynthesis to increase sugar production for the heavy fruit load.
Incredibly, the shoots that had set ‘terminal’ buds began regrowing! Perhaps terminal buds aren’t so terminal after all when supported with enough energy and the needed nutrition. These shoots continued to have healthy growth with tightly spaced nodes through the fruit fill period.
When trees have continuous healthy shoot growth with tightly spaced nodes, it is indicator they have enough energy to also set fruit buds for the following year, and we can effectively prevent biennial bearing.