One thing I love doing is visiting gardens during the Garden Conservancy's Open Days program. They are private gardens rather than public and are in general lovely, well cared for and an expression of the gardeners' personal style. There are usually a number of locally based tours of private gardens as well - Portsmouth, NH, has one every year in June and there's usually one in the Back Bay area of Boston I think.

Arnold Arboretum and Mount Auburn Cemetery are great for woody plants. Arnold is particularly good if you want to see a bunch of different cultivars of the same type of shrub such as lilacs. They have a list online of what blooms when.

Coastal Maine Botanical Gardens is in midcoast Maine and in Northeast Harbor is the Asticou Azalea Garden.

Garden in the Woods of the New England Wildflower Society is a good visit in spring, and Tower Hill Botanic Garden is run by the Worcester County Horticultural Society.

Bedrock Gardens in Lee, NH, is open two weekends a month during the growing season.

Here are a couple threads that may give you some ideas:

Open Gardens 2016

Open Gardens 2015

Ditto what NHBabs said although I have not been to all the gardens she mentioned. Last year made it to one Open Day and enjoyed it very much. They are always worth the drive. We also visited Maine Coastal Gardens in June and enjoyed it very much. Even if it's only a small landscaped area at a nursery, I enjoy a visit. Hope to visit Rocky Dale in VT this year. I have visited some NH gardens during Open Days. I'd like to see this year's garden tours list started since it usually takes some research to find them. I believe last year was the last time for Concord's South Church tour. I would especially like to find some Vermont garden tours since it's time to do some more exploring in that state.

Hi All,

It is lovely planning for spring in the middle of a blizzard, isn't it?!

While surfing I found a good list of New England gardens (many mentioned above):

Connecticut
"Must sees" include Elizabeth Park in Hartford, the state capital.
The Heritage Rose Garden is at its best in early to mid June.
In Old Lyme, American Impressionists of a century ago painted in what are now the grounds of the Florence Griswold Museum
In Farmington, the Hill-Stead Museum has French Impressionists inside; the outside looks like an English estate, complete with sunken garden.
Unique in the USA is the small English garden at the Glebe House Museum in Woodbury.

Maine
In Portland, don’t miss the peaceful Longfellow Garden.
For contrast, visit the Coastal Maine Botanical Gardens in Boothbay.
On Mt. Desert Island are two gardens. The Asticou Azalea Garden is modeled on classic Japanese designs, with a stream, pond, paths and statues.
Nearby, the English-style Thuya Garden boasts Thuja occidentalis, handsome white cedars.
In Augusta, the state capital, the Viles Arboretum (formerly the Pine Tree State Arboretum) features hostas, lilacs, chestnuts and conifers.
In the western part of the state, the McLaughlin Foundation, Garden & Horticultural Center is a century-old Maine farmstead surrounded by wildflowers and ferns.

Massachusetts
Boston boasts several "firsts": the Boston Public Garden is America’s first botanical garden (1837) and the Arnold Arboretum is the country’s oldest public collection of plants (1872).
Founded in 1829, the Massachusetts Horticultural Society is the nation’s oldest and is based at Elm Bank Reservation in Wellesley.
Nearby in Framingham, Garden in the Woods is the headquarters of the New England Wild Flower Society.
Tower Hill Botanic Garden near Worcester boasts a variety of gardens, walking trails, and two fruit-filled greenhouses — an orangerie and a limonaia.
In Stockbridge, Naumkeag is famous for the Blue Steps, with fountains, stairs and birches; in Lenox, The Mount’s magnificent gardens were designed by its owner, the author Edith Wharton.
Another wonderful garden destination is Cape Cod, where Heritage Museum & Gardens in Sandwich is known for rhododendrons and daylilies.
And while on the Cape, be sure to visit Martha’s Vineyard’s horticultural and botanical landmark, Polly Hill Arboretum, where rare trees and shrubs from around the world are set among stone walls, meadows and fields.

New Hampshire
New Hampshire’s state flower is the gorgeous purple lilac, Syringa vulgaris, imported from England and planted in Portsmouth in 1750. Today, lilacs thrive in spring in this seaside city where there is an annual Lilac Festival at the Wentworth-Coolidge Mansion.
For splashy color in mid-July, visit Rhododendron State Park in Fitzwilliam, in southwest New Hampshire. Here, the 16-acre grove of Rhododendron Maximum is the largest stand in northern New England.
For a historic garden, head for Canterbury Shaker Village in Canterbury, where the vegetable gardens were planted in 1795 and have been cultivated ever since.
Combine art and gardens in Cornish on a tour of the Saint-Gaudens National Historic Site.
On the coast, you'll find vibrant color in Portsmouth's Prescott Park, a spot for summer concerts and outdoor plays overlooking the Piscataqua River, as well as Fuller Gardens, a stone’s throw from the ocean with meticulously maintained formal rose gardens, a Japanese garden and English perennial plantings.

Rhode Island
Rhode Island takes pride in its gardening heritage; follow the Garden Path to see known and unusual destinations.
In Providence, the big draw is the new Botanical Center, the largest indoor gardens in New England, complete with a waterfall and ever-changing displays of headily-scented plants.
Newport’s grand mansions are all set in equally grand gardens: The Breakers (specimen trees, fabulous flower beds), The Elms (Classical Revival gardens) and Rosecliff (French-style gardens).
In Portsmouth, century-old Green Animals is America’s oldest topiary garden, with privet, yew and boxwood clipped into jolly teddy bears, a camel, elephant, even a giraffe.
Nearby in Bristol, Blithewold Arboretum and Garden is most famous for its spring daffodils, but is a delight year-round with its mature trees, roses, and perennials.

Vermont
In Manchester, Hildene is the former home of Abraham Lincoln’s son, Robert. See the cutting and kitchen garden; picnic in the fine perennial gardens, with roses, peonies, and lilies.
On the shores of Lake Champlain, near Burlington, Shelburne Farms is a working farm, where they are also restoring the grand Formal Gardens, with its lily pond, roses and other perennials, at Shelburne House overlooking the water.
One of a kind is The Path of Life, a public sculpture garden in Windsor, with 18 works of art symbolizing the journey from birth to death and beyond.
Celebrating its 30th birthday this season is the 6-acre Vermont Wildflower Farm. If you love snapdragons, bluebells and poppies, just head for Charlotte.

Link: http://www.discovernewengland.org/things-do/new-englands-glorious-gardens

Happy Travels!

A couple of comments/additions to the list for NH:

I wouldn't travel to just see the gardens at the Shaker Village, but visiting them along with the tour would be nice. I've done the tour a couple of times and enjoyed it; it's a beautiful spot. It does cost money and you want to check that a visit doesn't coincide with a big race at the race track within hearing distance in Loudon, NH.

The Fells in Newbury might be worth a visit. It also has an entry fee.

Last time I visited Prescott Park in Portsmouth they had a test garden for annuals, so I enjoyed seeing a whole bunch of different varieties and species there. The park itself is nice also and has theater presentations in the summer and since it is within a half hour (or perhaps less) of Bedrock Gardens in Lee they might make a good combined trip.

If you visit Saint-Gaudens Historic Site, there is a cut-your-own flower farm, The Song Garden, just a short distance up the St. Gaudens road.

Rhododendron State Park doesn't really count as a garden since it's a wild stand, but it's amazing to walk the paths under tall Rhododendrons, all in pale pink/white bloom in June.

Babs & Defrost, thank you so much, I am definitely planning on the Arnold Arboretum during lilac season! I will fit some of the other sites in as well.