October 26, 2023
THE LEAF: WHERE NATURE AND ARCHITECTURE CONVERGE
Nestled within Winnipeg's expansive 1,100-acre Assiniboine Park, The Leaf has emerged as an iconic attraction, inviting visitors into a world where architecture and the beauty of nature intertwine. Its four distinctive biomes, complemented by a classroom, restaurant, café, and banquet facilities, offer a captivating experience that fosters a profound connection between people and plants. Led by A49 Winnipeg in collaboration with KPMB Architects and alongside Blackwell Engineering, SMS Engineering, Introba, Transsolar and HFTC Planning and Design, The Leaf is a mesmerizing journey that harmonizes architecture with the natural world, inviting visitors to explore the delicate balance between humanity and plant life.
THE LEGACY OF ASSINIBOINE PARK CONSERVATORY
For over a century, the original Assiniboine Park Conservatory was a cherished refuge from harsh Manitoba winters with its lush and warm indoor horticultural sanctuary boasting over 8,000 flowers, plants, and trees. As the beloved original structure approached the end of its lifespan, the stage was set for the design of The Leaf. Since 2009, the conservatory had grappled with challenges relating to the building envelope, heating, and ventilation systems, making it increasingly difficult to maintain an acceptable indoor environment amidst extreme outdoor temperatures. It was during this time that a visionary concept emerged—a new facility that could harmonize with nature and address the interplay between plants, people, and community.
THE LEAF’S VISION
The design for The Leaf, envisioned by KPMB, draws inspiration from nature’s own patterns, such as the Fibonacci sequence, nautilus shells, and sunflowers. The organic form of The Leaf echoes the simplicity and complexity of the species housed within. The array of flora and fauna symbolizes the rich medley of cultures that exist within Canada. Expansive views in and out welcome visitors to explore the space and reflect on the beauty and wonder of natural ecosystems.
“For The Leaf, we wanted to create a transcendent experience that centers nature and sustainability. We wanted to do something innovative, something extraordinary, that could be enjoyed year-round in a city with extreme climates. The structure mimics nature with a roof that unfurls like a petal and the diverse biomes inside encourage curiosity, learning, and delight at every turn. The architecture goes beyond a mere place to house and showcase these climate biomes. The building itself is designed as an ode to the beauty of nature so visitors can feel the respect for the earth and environment from the very first look." Mitchell Hall, KPMB Partner
The Leaf was conceived with a singular purpose, to transport visitors into another ecosystem. Every nuance, from the arrangement of interior biomes, lighting schemes, and spatial arrangement, was meticulously organized to cultivate an environment that fosters wonder and engagement.
Aspiring for certification through the LEED 2009 green building program and guided by Transsolar’s expertise in engineering sustainable, environments, the design ensures optimal plant growth and a positive visitor experience. Challenges posed by Winnipeg's annual thermal fluctuations and intense solar exposure are met through passive strategies. Including a hydronic root heating system, natural ventilation with earth tube, and cooling through evapotranspiration using fog and high-velocity fans.
BIOMES AND DESIGN FEATURES
The four biomes offer an immersive experience across multiple stories. The Hartley and Heather Richardson Sub-Tropical Biome follows a meandering pathway that encourages discovery and transports visitors temporarily to another climate. The space includes Canada’s tallest indoor waterfall, which provides additional humidity to this biome. The Mediterranean Biome brings together the most vibrant colours, textures, and fragrances of native plants from Greece, Italy, South Africa, and Chile. The experience continues in the Babs Asper Display House, featuring dynamic floral displays and a phenomenal living wall installation, and finally, in the Shirley Richardson Butterfly Garden, where visitors interact with some of the most beautiful butterfly species in the world. Other spaces within the 90,000 sq. ft. facility include a large galleria, a restaurant, and a classroom space.
A significant building component of The Leaf is the unique building envelope, featuring an innovative 80-foot three-way helical spiral cable net roof structure supporting 3-layer Ethylene Tetrafluoroethylene (ETFE) pillows. ETFE, a lightweight and durable polymer film material, offers high transparency for plant growth, allows increased butterfly navigation, and other advantages over glass. This choice provides excellent light transmission, avoids excessive weight, and eliminates the need for heavy steel supports and shadows on the vegetation below. Located in Winnipeg, a city known for significant climatic extremes of over 75 degrees Celsius, The Leaf required sustainable solutions. The unfurling ETFE roof allows ample sunlight to reach the botanical garden while improving thermal performance as compared to conventional greenhouse materials.
Outside, the park’s exterior gardens and landscaping provide a seamless extension of The Leaf. Designed by HTFC Planning and Design, the outdoor spaces are perfect alcoves for community interaction, where nature’s wonders blend with social engagement. The Diversity Gardens stretch across 30 acres with six unique areas to explore: the Indigenous Peoples’ Garden, Kitchen Garden, Sensory Garden, Performance Garden, Seasonal Garden, and The Grove.
“As Winnipegger’s we celebrate the extremes of our climate, however even the hardiest of us appreciate a break from the long cold dry winter. The Leaf is an affordable, approachable and accessible urban oasis in the winter desert that transports one temporarily away and connects all people to plants in faraway lands. The facility is a fantastical technical achievement that elevates the spirit through the amplification of the natural systems to allow visitors to reawaken their appreciation of the horticultural world while the outside world is in hibernation.” Lee McCormick, Managing Principal, Architecture49 Manitoba
The Leaf at Assiniboine Park embodies the perfect blend of nature and architecture. It goes beyond being just an attraction; it's a symbol of our connection with the plant world. With its innovative design and sustainable features, it reminds us of the importance of preserving our environment. The Leaf stands as a testament to the unity between humans and the natural world, urging us to not only appreciate but actively protect the delicate balance of our planet. It's a lasting legacy that encourages us to embrace this vital relationship for generations to come.