The feeling that you’ve arrived someplace special starts before you even turn into the driveway of Coastal Maine Botanical Gardens in Boothbay. Sure, the daffodils poking up from chocolate-brown mulch are lovely. So, too, are the rambling rock walls. But if you look closely at the roadside plantings, you’ll notice a blanket of mosses and lichens planted in a curling pattern – like fiddlehead ferns or ocean waves.

It’s the facility’s logo – in plants – and it’s one of many small, thoughtful touches that make a visit to this natural wonder worth the trip.

Of course, it’s hard to miss the big, thoughtful touches: a two-tone granite rose set into a sweeping patio, a birch allee that stretches nearly a half-mile, and a visitor’s center that looks like a shingle-style mansion.

Everything here, from the tiniest patch of moss to the biggest slab of stone, is just so. And that’s just the way the garden’s founders envisioned it.

“It’s a very ambitious project,” Maureen Heffernan, CMBG’s executive director, said on a recent morning. “Our goal is nothing less than being one of Maine’s top attractions.”

Heffernan and the garden’s founders and staff will be one step closer to that goal on June 13, when CMBG holds its grand opening. Though portions of the garden have been open to the public for some time, the party will celebrate the achievement, in part, of a longtime dream.

In 1991, a group of Midcoast residents came together with a grand vision. They imagined a series of ornamental gardens that would unfold into untouched natural vistas. But this would be more than just a pretty place to visit.

“They’ve developed a plan that really makes it a complete botanical garden,” said Lois Berg Stack, an ornamental horticulture specialist for the University of Maine Cooperative Extension. Stack was a member of the design team for the overall property plan, and her involvement with the project stretches back at least a decade.

“It’s a place where gardeners of all ages can learn, both by viewing the gardens and by taking classes,” Stack said. “It’s a place where even nongardeners would enjoy simply being out in a large space that shows off the beauty of Maine. It’s a place where meetings might be held, or where research might be done. It has all of the things a full botanical garden would offer.”

All that and a stretch of pristine tidal shorefront, natural woodland gardens and native forest.

In 1996, the founders purchased 128 acres initially intended to be a housing development. That effort failed, but the parcel’s dramatic ledges and interesting topography were ideal for a botanical garden. In 2005, the garden received a donation of an adjacent 128-acre parcel from Pine Tree Conservation Society, making this the largest botanical garden in New England.

“Not all of it is developed or will be developed,” Heffernan said.

Given the scope of the project, the garden will continue to be a work in progress for the foreseeable future. Today, the campus includes the visitor’s center, as well as a central, cultivated area of roughly 7 acres that includes a kitchen garden, a rose garden with a soaring arbor, a lawn meant for weddings and parties, and a series of water features. Beyond that, a shaded trail winds down the hillside, toward the water.

Around every corner, visitors will discover another treat – whether a glistening glass orb sculpture, a reflecting pool carved from a boulder, or a whimsical fairy garden with “houses” created by children from bark and twigs. At the top of the hill, a path leads toward a rhododendron grove and the birch allee. At the bottom, a shoreline trail highlights Maine’s native flora.

The plant collection is constantly evolving. Among the current highlights are pink trillium, an impressive lady slipper collection, hardy roses and interesting ferns. Heffernan hopes to build the collection so visitors can discover new plants – things they wouldn’t necessarily see at their local garden center.

“Our whole mantra is ‘quality, quality, quality’ because we want to be here in the next 100 years,” Heffernan said. “We want to be seen as a state treasure.”

Donations and grants of all sizes – from $5 to $600,000 and beyond – have helped the organization raise $8.3 million to date. Another $7.75 million is needed to complete planned gardens and start an endowment.

“We’re very much a grass-roots project, and hopefully that augurs well for our sustainability,” said Heffernan, who moved here from Ohio 31/2 years ago, excited by the idea of starting a botanical garden from scratch. Though the project began in 1991, most of the construction work has taken place in the last three years.

The group hired a Washington, D.C.-based firm to design the visitors center, but most of the work has been sourced in Maine, including the extensive exterior stonework, the landscaping and the Craftsman-style dining tables in the cafe. On a recent visit, the prints and handmade books of local artists Kim and Phillipe Villard were on display, and Phillipe creates photographic posters for the gift shop, as well.

“We want this to reflect the best of Maine,” Heffernan said. “We’re developing what Maine’s best assets are – its natural beauty – without exploiting it. We’re hoping to enhance it.”

And those enhancements will continue. Two more major gardens are in the works: one for children and another that focuses on the five senses. For the youngsters, the design will focus on play, discovery and learning. Plans call for themed areas based on popular Maine children’s books. For example, there will be a “Miss Rumphius”-style lupine patch and blueberries from “Blueberries for Sal.”

In the Garden of the Five Senses, visitors will walk through a series of outdoor “rooms,” each of which will heighten a sense through intense fragrance, textured plantings, the sound of running water and the feel of a “reflexology” walkway of smooth stones underfoot. The garden will be fully accessible so visitors with and without disabilities can fully enjoy the experience.

Both projects have a target completion date of 2009, and with community and national support, this garden will continue to grow.

“I’ve been to so many gardens around the world, and our place is very special, with the coast, the ledges and the varying topography,” Heffernan said. “I really think we’re building one of the most beautiful gardens in the world.”

If you go:

Coastal Maine Botanical Gardens

Barters Island Road, Boothbay

Hours: 9 a.m.-5 p.m. Monday-Friday; 9 a.m.-6 p.m. Saturday-Sunday

Admission: Free for members and children 4 and younger; $10 for adults; $8 for seniors; $5 for children age 5 to 17

Information: 633-4333, www.mainegardens.org.

Grand opening celebration: 11 a.m. Wednesday, June 13, free and open to the public