This is the only picture I could find of my April-planted dahlia, Elise.
Scanning the New York Times this morning, looking for something to mock (just kidding!), I noticed this advice in the Q&A column.
The conventional wisdom is to plant dahlias on the estimated final frost date in your area—the same time that gardeners usually put out tomato seedlings.
And then writer Stephen Orr cited even more conservative dahlia wisdom from Frances Palmer, who thinks it’s even safer to wait until after the last frost date (whenever that might be), so that smaller tubers do not rot underground. This is all sensible advice that in the past I have always followed, sometimes first starting the tubers inside so that I would have flowers before September.
But last year I consulted another expert, my fellow ranter Michele, who suggested I plant my dahlia tubers deeper underground (6 inches) in APRIL, which, I need hardly say, is well before the last frost date in Buffalo. (Michele got this idea from an Eleanor Perenyi book.) And, you know what? I did it, figuring that with my miserable dahlia history, I had nothing to lose.
Reader, it worked. The little orange dahlia I planted in April was the only one to produce for me last summer, and this year I’m trying again. It was in a south-facing protected bed with a low brick enclosure around it. Last summer, I planted another dahlia tuber, one that I had started inside, after the frost date. Its spindly stalks pouted for 2 months, and then died.
And here’s some advice from another friend and expert, Mary Ann/Idaho Gardener, who pots her dahlias up in black plastic and leaves them in a sunny spot outside until they are advanced enough to plant them where she wants them. Like Palmer, she is concerned about the tubers getting too much moisture underground.
This year I plan to try both Michele’s and Mary Ann’s strategies. I’ll never have great success with dahlias—not enough sun and heavy soil—but they’re so lovely, I must continue. Tomorrow, I’ll be planting dahlias. Zone 5ers, your milage may vary!