The Emerson PurpleHull Pea Festival wants to create a little rotary tiller romance.

The annual festival and its feature event, the World Championship Rotary Tiller Race, a race of souped-up garden tillers, is always the last weekend in June. And that creates a problem.

“June weddings are very popular,” says festival spokesman Bill Dailey. “Inevitably, every year, someone just forgets and schedules their wedding on the same weekend as the festival and tiller race.

Through the years, the festival’s volunteers, regular attendees — even tiller racers have experi...