Bureau of Meteorology data shows most cherry growing regions have had the coldest winter for more than 20 years.
This means more chill units or chill hours—which may result in an increase in this seasons crop potential.
Low and low-to-medium chill cultivars such as the Royal series out of California, at say 350 to 750 chill hours, should continue to bear consistently well.
Lapins (bred in Canada) can also be included as low to medium chill, and is the reason it continues to be a consistent cropper when other cultivars from the same breeding station—such as Sweetheart and Sylvia—tend to fail to produce a viable crop.
A major difference between the sister cultivars Lapins and Simone, is that Simone requires medium to high chill hours (about 1000) which helps explain why in some seasons when chill is marginal, Lapins will produce a medium crop while the crop on Simone can be disappointing.
Ulster, Kordia and Regina require high chill hours, whereas Sylvia requires very high chill. This may help explain the reason for Sylvia’s inconsistent cropping even when good weather and healthy bee populations have been ideal for pollination. Often the flowers are there but fertilization fails and the flowers or young fruit abort and the crop fails to produce a payable return.
Reasons for crop failure
Many factors come into play when looking at the reasons for crop failure, chill hours is just one.
Pollination, elevation, timing of flowering of pollinators and rootstock choice are others.
It is said that varieties on Gisela rootstock require less chilling than most other rootstocks.
One last season for some varieties
So before you remove those cherry varieties in your mix of plantings that have failed seriously over the last ten years, consider keeping them this season at least, as they may produce a crop.
And even if they do, you may still wish to remove those trees after harvest—especially if you have to wait another ten years or so for a chilling winter like we have just had to get a really good crop.
Other risks
With an El Nino predicted to be on its way, a dry season might be imminent.
However, rain and adverse weather is still the highest risk to growing a profitable crop.
It is not over until the cherry crop is picked, packed, marketed and the money is in the bank.
For more information, see Tree Fruit September 2015
