Harris Center for Conservation Education, 83 King’s Highway in Hancock, will host “A Monadnock Garden Day: Gardening in a Changing World” Saturday, June 15, from 10 a.m. to 4 p.m.

Gardening experts Page Dickey, Edwina von Gal, Helen O’Donnell and John Gwynne will speak. Dickey is a founder of Garden Conservancy’s Open Days Program who has written eight books. Von Gal creates landscapes focusing on simplicity and sustainability for private and public clients around the world and founded the Perfect Earth Project to promote toxin-free landscapes for the health of people, their pets and the planet.

O’Donnell is a professional gardener, designer and grower who co-owns and manages Bunker Farm in Dummerston, Vt. with her husband, sister and brother-in-law. Gwynne is a co-operator with Mikel Folcarelli of Sakonnet Garden in Little Compton, R.I., trained as a landscape architect and headed design at the Wildlife Conservation Society for 26 years.

A brown bag lunch by Fiddleheads Cafe will be provided, and regional nursery vendors will be onsite. Coffee, tea and snacks will be served starting at 9 a.m., with opening remarks at 10 a.m.

Cost is $100 per person for Harris Center supporters, and $110 for all others. Registration is required at harriscenter.org/events. For information, contact Susie Spikol at spikol@harriscenter.org.