Fruit trees, including peaches and plums, rely on a period of winter dormancy, triggered by a specific number of “chill hours” or periods of cold weather that help trees reset and prepare for spring growth.

In Texas, where winters can be unpredictable, achieving the right number of chill hours is increasingly uncertain.

“This year, chill was marginal,” said Larry Stein, Ph.D., Texas A&M AgriLife Extension Service horticultural specialist and professor in the Texas A&M Department of Horticultural Sciences, Uvalde. “It wasn’t the best, but it wasn’t the worst. Trees did bloom but then we had freezes.”

Barely any chill

When freeze events hit after trees bloom, it can damage fruit sets and compound chill hour challenges.

“We’re dealing with a double whammy,” Stein said. “Not only was the bloom sporadic due to marginal chill, but the freezes killed some of the early fruit.”

Texas growers are seeing uneven tree production, with buds emerging inconsistently across branches.

“A well-chilled tree will leaf out all at once. But when chill is lacking, the growth is patchy,” Stein said.

Varieties matter

To avoid a disappointing crop, Stein said the importance of choosing fruit tree varieties suited to the specific chill requirements of Texas’ regions is critical.

Growers and home gardeners should consult with local county AgriLife Extension offices and use resources like the Aggie Horticulture website, which features maps and fact sheets outlining chilling zones and variety recommendations, he said.

“If you pick a variety that needs too little chill for your area, it’ll bloom too early and get frozen out,” Stein said. “If you plant one that needs too much chill, it may never bloom or leaf out properly.”

With chill hours becoming less predictable because of climate variability, Stein said selecting the right variety is more crucial than ever.

“Chill is a real thing,” he said. “And it can make or break your fruit crop.”