Celebrate the blossoming of spring with the annual perennial plant exchange, where you can trade your perennials (in pots or plastic bags) with local green thumbs who share your passion for gardening. This free event only lasts as long as there are plants available for trading so make sure to be prepared, rain or shine. The event will be hosted in the Maple Grove Community Center parking lot, near the skate park. All ages. Free admission. Saturday, 9:30 a.m. Maple Grove Community Center, 12951 Weaver Lake Rd., 763.494.6535; maplegrovemn.gov.