Aquatic Garden

Native and exotic plants

This garden contains aquatic and wetland plants from peatlands, marshes, lakes and rivers in Quebec and elsewhere in North America, along with a number of species from other continents. You will surely find inspiration for the design of water gardens.

The role of the plants in their ecosystem

Aquatic and wetland plants play a role in maintaining the biological balance in their ecosystem. They filter, purify and help oxygenate the water, limit the growth of algae and offer shelter for wildlife.

These plants are a vital part of wonderfully diverse but often little-known habitats that are increasingly at risk. It is urgent that we act to preserve such remarkable ecosystems.

Plants that share a home, but have very different backgrounds

While aquatic and wetland plants are grouped together because they share a similar habitat, they belong to various taxonomic groups.

In the wild, they basically fall into three categories, depending on how much of the plant is immersed.

• Submerged plants grow completely underwater year-round, except for their flowers, which usually emerge at pollination time.
• Floating-leaved plants produce adapted leaves to stay on the surface of the water. Their roots may be anchored to the bottom or the plants may float freely.
• Emergent plants grow in damp soil or shallow water. Their roots are anchored in the soil, while their stems and leaves are mainly held above the water.

Well adapted to their habitat

Aquatic and wetland plants have evolved to suit their environment. These adaptations are most visible in floating-leaved and submerged plants.

Submerged stems and leaves usually have no supporting tissues, but instead contain air spaces for buoyancy. These plants often have minimal roots or none at all, because water and nutrients are absorbed directly by the other submerged parts. When present, roots serve mainly as an anchor.

Leaves may be aerial, floating or submerged. Aerial leaves are similar to those in plants that grow on land. Floating leaves are rounded and often thick and waxy but flexible, allowing them to stand up to the wind and waves. Their long, flexible petioles also let them adjust to changing water levels. Submerged leaves are thinner and their shape allows for gas exchange underwater.

These plants usually hold their flowers at or above the surface so that they can be pollinated by the wind or insects.

Invasive exotic wetland plants

Most exotic plants that are introduced intentionally or accidentally come from other continents. Many of them have become well established and today account for one-quarter of all plants in Quebec. These naturalized plants are termed “invasive” when they spread to the point that they interfere with human activities or biodiversity, as is the case with some of the plants presented here in the Aquatic Garden.

Habitat destruction and invasion by exotic species are the main factors threatening our planet’s biodiversity. Human activities related to agriculture and residential and commercial developments are largely to blame for allowing these opportunistic plants to quickly colonize disturbed habitats. The lack of predators and diseases also makes it easier for them. Their large numbers threaten the diversity of plants and animals in various ecosystems and it is very difficult and costly to eradicate them once they become established. The best way to avoid this happening is not to grow them in your garden!

For more information

Invasive alien species strategy - Environment Canada