I've poked around a bit and found some more plant sales, so here's the most recent list. Send me any sales you know of in Maine and I'll post them.
Annual Perennial Plant Sale - Order Now!
Peace through Interamerican Community Action (PICA), Bangor
Pre Order plants by May 1, pickup on the weekend of May 20
Laudholm Farm Native Plant Sale
Wells Reserve at Laudholm Farm
Pre-order plants by May 10, pickup Sat/Sun June 2, 4-6 pm; June 3, 9 am-1 pm.
For more information
Plant Sales by Date
Saturday & Sunday May 13&14, 9 am-5 pm,
Wildflower Celebration and Plant Sale
The McLaughlin Foundation Garden and Horticultural Center - 97 Main St., South Paris, ME
Season-opening plant sale specializing in wild flowers and perennials. Enjoy Bernard's [McLaughlin] wild flower collection in bloom while you choose additions for your own garden. The gift shop and house will be open.
Saturday, May 20, 9 am - 4 pm
Bowdoinham Library Plant Sale
Bowdoinham Town Hall
Don't miss this one! Bring a box, or plastic bags, or both.
For more info
Saturday, May 27 9 a.m. to 2 p.m.
The Annual Master Gardener Plant Sale will be held at the Barron Center in Portland from Brighton Ave, opposite Lowe's, at ME Tpke Exit 48.
The proceeds provide scholarship money for Maine students studying horticulture.
Saturday, May 27, 8 a.m. to 3 p.m.
Maine Rose Society Annual Plant Sale
60 varieties, $14-$17 ea
The Barron Center, Portland
Saturday, May 27 from 9 a.m. to 1 p.m.
The Bridge Academy Public Library
Annual Book and Plant Sale on
Old Town Hall, Dresden
Saturday-Monday May 27-29
Friends of the Maine Wildlife Park Annual Plant Sale
Rte. 26, 3 miles from Gray Center.
This volunteer group helps out the Wildlife Park in so many ways. Learn more about their ongoing projects and enjoy great spring plant deals with plants from their own greenhouse!
Perennial and Herb Sale
Society for the Preservation of New England Antiquities
Marrett House in Standish
Call 207-384-2454 for more information
Saturday, June 3rd, 10 am - 2 pm
Peerless Perennial Plant Sale
The Morris Farm, Rte 27, Wiscassett
June 10-26, 9 am – 4 pm Tuesdays-Saturdays
Home Farm and Museum, UMaine Orono
Herb and vegetable seedlings
Saturday, June 24, 9:00 am to 2:00 pm
7th Annual Book and Plant Sale
Waterville Area Humane Society, 120 Drummond Ave, Waterville.
For more information, call WAHS, 873-2430.