Source: https://www.homesandgardens.com/gardens/what-is-no-mow-may
What is No Mow May – why and how to take part
To join in with No Mow May, leave the lawn unmowed. ‘Wildflowers that give nectar and pollen to honey bees will grow and bloom if we do not mow them down before they flower,’ explains Todd Hardie, considered the bee guru of the north country, and adviser to specialty food company in Vermont Runamok. ‘This food is important to honey bees and all pollinating insects as they need this nourishment for their families to expand in population in the early part of the season.’