Last weekend Blackberry Winter struck here in the Blue Ridge Mountains of North Carolina. As a Yankee, I learned about the “little winters” of the Appalachians in 2020, during my first full year of southern gardening. I was lulled into complacency by the balmy late spring temperatures and planted my tomatoes, peppers and cucumbers. Then came the cold snap with hard frost warnings. I scrambled to cover my tender plants and fought with the winds that ripped off my raised bed covers. There were casualties. When I related my woes to a local old timer, he chuckled, “That was just Blackberry Winter, in these parts we don’t set our summer garden out ’til Mother’s Day.”
Since ancient agricultural times, farmers have followed phenology, the periodic events of biologic life cycles. They relied on nature signs to know optimal planting times. They’ve learned over time to observe seasonal variations in climate, like when plants first leaf and flower in the spring, when they see the first butterflies or the return of migratory birds. In the fall they take note when the deciduous trees leaves change color and drop and other signs that indicate Indian Summer.
Seasonal temperature variations are relatively predictable, but they don’t climb in a smooth slope from cold to hot and back, they fluctuate with small “blips” called singularities, that is they happen in at least 50% of the years.
Here in my area of the Appalachian Mountains just south of Boone, we experience the singularity of Blackberry winter, in late Spring when the blackberry bushes are in bloom. It’s a cold snap, that can last a few days or a week bringing a hard frost or even snow, that interrupts the warm spring weather. The cold weather signals the canes to grow.
In modern times, we can consult the paperback Farmers’ Almanac or online to find out the average frost dates in states and cities. Or you can start your own chart for the specific microclimate of your gardening area.
I wasn’t taken aback this spring. My seedlings are still safe in the greenhouse, except for little hardening out holidays, where they’ll remain until their coming out party on Mother’s Day.