A Chilling Tale of Three Blueberry Cultivars

The number of chill hours we received this year has been lower than usual (see Chill Hour link on right side of this page). I am in the process of accumulating chill hour data from the last 15 years or so to see how (or if) it has changed over that time period. At any rate, this year was somewhere between 500 and 600 hours here in Poplarville.  Enough for most blueberry cultivars, but not all. To this point, see the photo below.

From left to right: Springhigh, Jewel, and O'Neal southern highbush blueberries. Notice that O'Neal has no leaves compared to the other two.

From left to right: Springhigh, Jewel, and O’Neal southern highbush blueberries. Notice that O’Neal has no leaves compared to the other two.

Springhigh has a low chilling requirement of 200 hours. It is also very early blooming which causes problems in our location most years. This cultivar was released in 2005 out of Florida.  Jewel has a similar chilling requirement of about 250 hours. It too is from Florida. O’Neal is much different from the other two.  For flowering it requires about 400-500 hours of chilling; however the leaves have a higher requirement. Although I would not consider the flowering good on this bush it has some. Leaf development is known to be slow and sporadic on O’Neal anyway in the spring. This cultivar is from North Carolina.

I suspect that the amount of chilling we received fell in the area of enough for O’Neal flowers but not quite enough for O’Neal leaves. Leaves will continue to emerge but may take longer than normal. That delay in full leafing may affect the quantity and quality of the crop on O’Neal, whereas both look fine on Springhigh and Jewel.

This publication from Georgia has good information on these cultivars and chill hours.

Mississippi Chill Hour Accumulation

I have previously wrote on the topic of chill hours, but I also get a lot of requests for what the accumulated hours are for the season.  This year I will be posting them on this site on the page entitled Chill Hours (on the right hand side of your screen).  By visiting this page, you will be able to keep up to date on the accumulated chill hours as reported by locations in five counties in Mississippi — Copiah, George, Jones, Lee, and Wayne.  The recordings are reported by volunteers, so they may or may not be available for each week.  In the future I hope to put together data from previous years (at least those I have) and also make them available on the site.

As of today, the first posting is up.  Each recording season runs from October 1 to April 1 of the following year.

Mississippi Vaccinium Journal April – June 2014

The latest issue of the Mississippi Vaccinium Journal is now available.  It is below as a pdf.  Remember, you can always access past issues here:
In this issue we discuss chilling hours, recap the 2014 blueberry workshop, Kudzu bug and more.
If you have any questions or comments please let me know.