November 26, 2024

LSU AgCenter's Weekly Message

Oldies are Sometimes Goodies: An Update on the Blueberry Variety Demonstration

In November 2020, we planted three plants each of 31 blueberry varieties at the Hammond Research Station. Last year, I wrote about what we’d learned from the 2023 season, when many flowers and unripe fruits were killed by a late freeze, before the fruit could ripen.

The 2024 season was far better for blueberry production, and many people had abundant harvests. We were among them.

Our demonstration includes both rabbiteye and southern highbush varieties. Rabbiteye blueberry (Vaccinium ashei AKA Vaccinium virgatum) varieties include ones that have been planted in the Deep South for many years. They are more forgiving of less-than-ideal soil conditions and can live for a long time (40 years or more, in some cases).

Southern highbush blueberries are crosses between the northern highbush blueberry (Vaccinium corymbosum) and other native blueberry species, such as Vaccinium darrowii. As a group, these fruit earlier than rabbiteye varieties and are perceived by some as having better fruit quality. They dominate the commercial blueberry industries in states like Georgia, Florida, and North Carolina. However, they are more finicky about soil conditions than rabbiteye blueberries are. Having an appropriate soil pH and good drainage are critical when growing these. They also tend to be more susceptible to plant diseases.

The blueberry planting at the Hammond Research Station is a demonstration rather than a research study. To be legitimate research, varieties would need to be replicated randomly within the area so that we could be confident that differences were due to the varieties themselves and not to, e.g., soil conditions in the spot where a variety was planted. Nevertheless, collecting yield data from this demonstration does give us some insight.

One thing I took away from this season was a reminder that the longstanding popularity of old standards is often justified. Tifblue, which was released in the 1950s, bore the most fruit (19.2 lb per plant). The second-place winner was Ochlockonee, a late-season variety that was released in 2002 from the University of Georgia’s breeding program. It bore 18.3 lb per plant. Among rabbiteye varieties, Ochlockonee has a relatively high chilling requirement (650 to 700 hours). This is more than what we get in some years. One thing I’ll be watching for is how it performs in seasons after a warm winter.

The long-popular Brightwell came in third, at 17.5 lb per plant. Brightwell also stood out last year for having a respectable amount of fruit (based on visual observation) in spite of the late freeze. Premier (12.2 lb per plant) and Austin (12.1 lb per plant) rounded out the top five.

Yields (lb per plant) of other rabbiteye and related varieties were as follows: Alapaha (9.6), Centurion (8.5), Climax (5.0), Columbus (5.4), Delite (6.5), DeSoto (6.8), Krewer (2.0), Onslow (5.4), Pink Lemonade (3.5), Powderblue (9.1), Robeson (2.1), Titan (1.6), and Vernon (6.8). (Pink Lemonade and Robeson have both rabbiteye and non-rabbiteye plants in their backgrounds, but they’re grouped with the rabbiteye varieties.)

All of the top 10 producers were rabbiteye varieties, except for Legacy, a southern highbush variety released by USDA in 1993. It produced 8.4 lb per plant. Legacy has a relatively high chilling requirement (approximately 500 to 600 hours) among southern highbush varieties and flowers late enough that it seems likely that it will escape late freezes in most years.

Yields (lb per plant) of other southern highbush varieties were as follows: Camellia (1.1), Colibri (0.6), Emerald (1.9), Farthing (4.6), Gupton (6.1), Keecrisp (2.8), Miss Lilly (0.9), Paloma (0.3), Patrecia (0.3), Pearl (6.2), Star (0.4), and Suziblue (3.8).

Yields of the earliest ripening varieties were generally unimpressive. However, this likely wasn’t solely the fault of the varieties. When there were fewer berries (as there were at the beginning and end of the season), birds likely consumed a larger proportion of them. Likely less of a factor but still fair to note is that a few of the earliest varieties had small amounts of fruit before yields were documented.

The dedication of volunteers with the Louisiana Master Gardener program, several of whom were present at almost every harvest for more than two months, made this data collection possible.

I’ll write more about when varieties ripened, as well as preparing for blueberry planting, in the next article.

Let me know if you have questions.

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Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

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