Did autumn fail to complete the job of leaf fall?
If it appears that not enough cherry leaves have dropped from the trees by now, and there’s a concern that dormancy is starting late, then consider a spray application (or two) to hurry leaf fall along.
In Australia, dormancy—or the chilling period—may begin about May 20 (allowing for climatic variations). So trees mostly still full of leaves may need a little persuasion to help them drop.
Sprays may help
The normal copper sprays help induce leaf fall. Sprays of urea, zinc and other compounds can also assist.
Should leaf abscission take place in a timely manner, that delay could slow the nutrient transition from the leaves to the roots, not only halting the flow of nutrient, but also shortening the winter chill period.
Publications of interest
It is not my intention to name compounds and rates for spraying, therefore take some time to visit the website below, and learn more about the subject and what actions could take place to gain a more positive result.
Both publications are from treefruit.wsu.edu.
The first to consider is, Early fall defoliation in sweet cherry. Find it here. The other is, Implications of delayed leaf abscission for spring nutrient management. Find it here.
Consider growing conditions
The growing conditions last season in Australia were such that growers will be keen to do whatever is required for the cherry orchard to be best placed in order to produce a profitable crop of high quality.
See this article in Tree Fruit May 2023
