The Maison de l’Arbre Frédéric-Back at the Jardin Botanique de Montréal (JBM) was constructed in 1996 in the northeast part of the garden, showcasing both the Tree and the surrounding collections of the Arboretum. This impressive, wooded area was established in 1960 following the rehabilitation of a municipal quarry transformed into a landfill.
The Pond of the Maison de l’Arbre, located adjacent to the house, constitutes an educational station of phytotechnologies to address problems linked to the environment and sustainable development in the garden. This pond was transformed into an artificial wetland in 2000. Since then, the pond and its banks have been invaded by unwanted plants such as the common reed (Phragmites australis). Their presence and proliferation made the pond a closed wetland that visitors could no longer contemplate and appreciate.
Therefore, to restore the pond to its desired initial state, it became necessary to carry out its restoration. The project aims to design a healthy and ecologically sustainable pond, free of invasive plants, and to landscape it in a way that provides a lush scenic experience, seamlessly integrated into its environment and reflecting JBM’s educational mission. Several key factors essential to water health are considered, such as oxygenation levels, exposure to sunlight and prevailing winds, maximum occupation of banks by native plants, the presence of thriving aquatic plant beds, and the optimal ratio of aquatic plants to open water.
When implementing phytotechnologies in design, the challenge was not just to install them but to design them to maximize their performance and ensure their long-term effectiveness. The pond’s perimeter has been slightly enlarged to better connect it to its immediate environment, and its bathymetry was significantly altered to create favorable shores for aquatic plants and provide a central and deep open water zone. Elements serving as retaining walls in the pond, such as gabions, also serve as attachment points for vegetated rafts and floating islands; they also offer a secure perimeter passage below the water for maintenance operations.
Planting, a major element of phytotechnology, is designed to compete with invasive plants and optimize the growth of beneficial ones. The banks, densely populated with various native plants, are complemented in their filtration role by vegetated floating rafts and islands made up of a floating system of recycled material covered with coconut fiber. Their planting enhances phosphorus absorption during low-water periods. Together, they enrich the existing wildlife habitat. Areas to the south of the pond are designed to provide shade, preventing the development of invasive plants requiring sunlight. It has been noted that vegetated rafts and floating islands also contribute.
Planting thus sculpts the landscape; varying heights, textures, and colors create thresholds, points of interest, and foster contemplation. Viewpoints are created from and towards the surroundings, while the mobility of vegetated islands brings dynamism to the scene, introducing change. On the west side where the wind comes, a few breakthroughs created through the thuja massif leave openings to encourage the wind to caress the water surface, preventing stagnation.
Composed of natural stones of various sizes, the upstream cascade of the pond enriches the auditory landscape and supplies fresh water to the pond. The cascade operates from May to November, splitting into three cascades allowing aeration of the pond. A quantity of water will be filtered via a system of tanks under the waterfalls filled with a filtering substrate to adsorb soluble phosphorus. Rising from the pond’s overflow, a stream deploys small cascades and then follows a calmer course through the garden’s collections before reaching a naturalized reservoir bordered by natural stones and native plants. Discreetly integrated into the ash woodland, a pumping system returns water from the reservoir to the top of the cascade, ensuring a circulation loop. The pump operates on solar energy from an existing but unused garden solar panel. The water is renewed every two months with fresh water from an existing artesian well, and the recirculation of water in the system takes place every twelve days. Working with these existing elements is a major aspect of the project.
To offer observation and contemplation spaces connected physically and visually to their environment, belvederes, ramps, and platforms adorn the area, accessible to all. Their materiality and morphology reveal an analogy to the site’s history. Thus, the three layers – quarry, landfill, and arboretum – are embodied not only in the wooden benches (limestone, steel gabions, wooden seats) but also in the guardrails (voids, steel plates, and wooden posts). While the profile of galvanized steel supports outlines the relief of the former quarry, akin to the Arboretum, wood remains the top layer in contact with users.. 4,991
Location: Jardin Botanique de Montréal – 101 Rue Sherbrooke Est, Montréal, QC H1X 2B2, Canada
Design year: 2017
Year Completed: 2021
