Kirkland’s Evergreen Academy preschoolers released thousands of ladybugs into the school’s garden in celebration of Earth Day.

Students and teachers also planted flowers in the school’s playground and surrounding campus.

Evergreen Academy’s Earth Day is an annual celebration that serves as a chance to combine learning with fun, as students have been studying the biological defense system that ladybugs create for the environment. As one of nature’s most helpful creatures, ladybugs feed on aphids (plant lice) that are harmful to gardens, trees and shrubs, according to an academy spokesperson.