Digging Deeper



Digging Deeper

Digging Deeper

When we opened our doors to the public 10 years ago, the facilities were designed to accommodate 40,000 guests annually. Yet in 2017, we welcomed over 190,000 visitors. Even after the first year, it was obvious that we were rapidly outgrowing our current Visitor Center. Over the years, the space was retrofitted to increase office area and better utilize the remaining space for the benefit of guests. In addition to re-configuring the Visitor Center, the Bosarge Family Education Center was built to provide more education space and house additional staff. However, between 2007 and 2017, our staff grew from 10 full-time and 12 part time/seasonal to 52 full time and 50 part time/seasonal, while visitation increased five-fold. It became clear that no amount of additional retrofitting could solve what is essentially a problem of space. To ensure our infrastructure is able to support current as well as future visitation, we’ve begun implementing phase two of the master plan. The master plan builds capacity to serve the current and future number of guests, while also creating additional space for education, horticultural research and a growing staff.

Visitor Center

Construction on our new visitor center is planned to be complete spring of 2018. Landscape architects Nelson Byrd Woltz, known for their ecologically sound design, sited the new building in a former parking lot. Designed by Steven Blatt Architects of Portland, this two- and three-story shingled building will provide three times the square footage of the current single story visitor center while utilizing practical, sustainable passive building standards.

Guests will enter through the central lobby with access to an expanded membership area, guest services, an information kiosk, restrooms and the gift shop. A separate snack bar will be located on the terrace behind, with bench seating. Groups will have a dedicated entrance near a bus parking area. Staff and volunteers will enter though a separate side entrance.

The first and second floors of the building will contain private and shared office space and communal space for staff and volunteers, as well as generous storage and facilities.  The third floor will feature a meeting room that can seat 75, which will also be a valuable resource for the community. We have designed this building to be easily expandable if necessary in the future and we have incorporated 30% more office space than we currently need to provide a buffer for growth.

Entry Court and Gardens

The entry court and gardens adjacent to the new visitor center will feature a blend of native and ornamental plants, as well as stonework inspired by our Maine landscape set amid a brick terrace. There will also be accessible parking and a drop-off area.

With nearly an acre of planting area, the entry gardens will fall somewhere between our Lerner Garden of the Five Senses and Bibby and Harold Alfond Children Garden in size and serve as a beautiful introduction to all we have to offer at CMBG. The garden beds will also include riverbed stones to collect roof run-off. This run-off, after being filtered, will then replenish our natural wetland areas.

Parking and Infrastructure


Our original parking lots consisted of 4 gravel “pods” that could accommodate a total of 125 cars. In response to the unexpectedly high visitation we experienced, our parking areas were expanded to provide spaces for a total of 340 cars. These spaces regularly fill on high summer days and during Gardens Aglow, due both to the increase in visitation and to a three-fold increase in length of stay as more garden areas have been added and guests linger longer. Non-visitor pressure on parking has increased greatly, too: staff has quadrupled, and there has been a similar trend among volunteers. Expanded educational offerings, more field trips, increased rentals and more have put further pressure on parking.

Because the original 2004 master plan greatly underestimated parking needs and did not plan for growth, expanded parking had been added with no clear circulation plan. This led to a confusing flow for visitors as well as safety concerns. In addition, gravel lots are dusty in summer, muddy in spring and icy in winter. Gravel is also worse for the environment than asphalt because of dust, erosion and storm runoff issues.

A better solution to parking was a top priority for phase two of the master plan.  The current parking configuration is not only confusing, but because of a lack of crosswalks, sidewalks, clear vehicular circulation and ample lighting, it is also dangerous for pedestrians. Furthermore, much of it is located close to existing gardens.  To expand the gardens, the existing parking would either have to be moved or gardens would have to be built around it.  Moving the lots was clearly the preferable solution: parking on the periphery creates a far safer and more seamless experience for all visitors.

The plan we are implementing converts most of the existing parking into gardens and serves as sites for the new visitor center and conservatory.  Many of the natural features on the property that make CMBG especially appealing to visit–like the wealth of rocky ledges, steep slopes, wetlands and shoreland–create many challenges in siting parking locations. After exploring several different options, the clear choice was to relocate parking farther down the ridge from where it now lies.  This area contains the poorest soils and fewest wetlands, and the gently sloping topography allows us to create a tiered set of pods separated by 15-20 foot planting zones in much the same fashion as the original lot. Out of concern for wetlands and due to setbacks from our neighbors, we scaled back the size of the parking lot several times.  When complete, the parking area will consist of 12 individual pods for a total of 650 spaces, including 24 accessible parking spots and spaces for staff and volunteers.  A separate bus parking area will accommodate buses and RVs.  The parking area built near the Bosarge Family Education Center will be reconfigured to create a travel lane for deliveries, shuttles and school buses.  This will reduce the total number of spaces available there, but will bring the total to 700 spaces. For busy events like Gardens Aglow, timed ticketing and shuttles have proven effective.

The main parking areas will be constructed using porous asphalt.  This technology allows stormwater to flow through the asphalt to a retention basin underneath designed to capture and filter all the rain from a 25-year storm event.  The basin is filled with coarse gravel above and fine gravel below.  As stormwater flows through the gravel, pollutants and sediments are removed and the velocity of the water is greatly reduced.  Treated stormwater eventually makes its way to pipes at the bottom of the basin where it is slowly discharged into the forest beyond.  To construct the basins and to provide the proper slope and grade for ADA compliance and safety, roughly four acres of forest were cleared for construction.  More than 40% of this area will be replanted primarily with native evergreen trees, then transition to mixed plantings for wildlife habitat.  To create this forested and garden-separated parking, over 10,000 trees, shrubs and both native and ornamental plants will be installed by our horticulture team.  It will be the largest planting project and the largest garden area ever built at CMBG.

Discovery Bridge

A bridge is a strong metaphor, suggesting a connection between two places, or crossing a threshold. When guests exit the visitor center, they will proceed across a 200-foot long and 12-foot wide pedestrian bridge that crosses over part of a large forested wetland. The bridge ends at a raised terrace that will overlook the conservatory and surrounding gardens.

While this bridge will serve an important practical role in protecting a unique wetland area, metaphorically speaking, it will provide a wonderful transition to the joy of the gardens and nature beyond. The bridge will be constructed like the marine piers so common in the area, but will use native, rot resistant black locust rather than pressure treated or synthetic wood for decking. The bridge will have a subtle s-curve and, at its highest, will stand 15 feet above the ground. It will provide a safer experience for pedestrians, separating them from cars, buses and our accessible shuttles.

Plant Nursery and Horticultural Research Center + Homestead

Towards the southern tip of the property lies the foundation of an old farm homestead. This will be the site of a new plant nursery that will allow us not only to grow more of our own plants on site for our gardens, but also to develop and test new plants for northern landscapes. This important part of our mission – research – has been the piece we have long dreamed of fully implementing, creating opportunities to better document Maine’s beautiful rare native species, to study the spread of species from the south due to a changing climate, and to develop plants that are better suited for our northern and coastal landscapes, among many other things.

This nursery will also include an herbarium and botanical research program that is focused on wild plant diversity and conservation in the MidCoast region. Studies of this kind have not taken place in this area for many years, and the landscape has changed since nineteenth-century botanist Kate Furbish first collected, classified and illustrated Maine’s native flora.

The homestead will also be rebuilt to provide a space for learning and classes with a stronger emphasis on food and food security. This will include demonstrations of year-round, home-scale fruit and vegetable production, as well as classes on preserving and serving these foods and more. This will also be an area that will provide a continued focus on sustainability, including expanded composting, water conservation and alternative energy projects.

Expanded Education Campus

Our current education area will benefit not only from the added space due to moving administrative staff out of the Bosarge Family Education Center and into the new visitor center, but also from the eventual addition of an expanded education campus around it. This campus will include our current education building, a new youth education building and a “wet classroom” for hands-on learning, an expanded facility for our Horticulture Therapy program and a Center for Professional Horticulture, among other things. The Center for Professional Horticulture will provide vocational and continuing education for green industry professionals and those seeking a career in the fields of public horticulture, lawn care, landscape design and installation, nursery management and arboriculture.

Conservatory + Pond, Bog and Stream Gardens

Although it is a few years out in the plan, a glass conservatory will be the cornerstone of our efforts to build year-round visitation and will create year-round jobs and opportunities for our area. The conservatory will create a space for late-winter and early-spring shows, such as specialty orchid displays and butterfly shows, during a time of the year when not much else is in bloom. Based off of the shape of the classic saltbox home, the conservatory will be specially built for cold Maine winters while still providing an environment for out-of-season plants.

Utilizing an innovative double layered energy curtain to reduce heat loss in the colder months, the conservatory will also feature passive natural ventilation and cooling to remove the need for forced cooling in the summertime. Featuring cold-tolerant plants in the wintertime will also help to keep our heating costs low.

The conservatory and surrounding gardens will be installed in what has historically been a parking area here at CMBG. With parking moved to the periphery, the conservatory and a 250,000-gallon pond and surrounding gardens will be installed in its place. This pond will include a pump station and will be available 24/7 to local first responders. A stream and bog garden will also be added, expanding the diverse plant communities on our property and creating better habitats for wildlife.


Restaurant Pavilion

To catch up to current visitation numbers while also providing a buffer for growth, the decision was made to build a new visitor/administration building and gift shop and convert our existing visitor center into a restaurant pavilion. This will be implemented in stages. The concept with this pavilion is to retain the character and footprint of the original building, but to expand the kitchen into the existing offices, and convert the lobby, ticketing area, conference room and the gift shop into healthy, family-friendly buffet-style service and seating. The existing café space will be a separate, more intimate restaurant featuring table service. Eventually, a three-season structure will be erected on the terrace outside and will serve pub-style food and drink. The kitchen will also service the conservatory and the snack stand adjacent to the new visitor center.