Global menu

The Green pages

Gardening for biodiversity

A garden for biodiversity – Heart-leaved foamflower (Tiarella cordifolia)
Photo: Gilles Murray
 Tiarella cordifolia

Gardening for biodiversity isn’t rocket science. If you feature native plants and follow these tips, you’ll be inviting nature to your doorstep. Meaning you’ll have a chance to make some wonderful discoveries – and in your own backyard!

The importance of native plants in the garden

Native plants of Québec are being used more and more in landscaping. And with good reason, since most of them are easy to grow and are as attractive as ornamental plants hailing from other parts of the world.

In addition, they play a key role in maintaining the biodiversity of our territory by serving as food, shelter and breeding grounds for indigenous fauna. In some cases, the relationship between the organism and the plant is so important, the host can’t survive without it. That’s notably the case with certain butterflies, who depend entirely on their host plant to reproduce. The monarch, whose survival requires the presence of milkweed, is an excellent example.

It’s not necessary to grow native plants exclusively in order to promote biodiversity in the garden. However, native species are more likely to respond adequately to the needs of indigenous fauna because of the close links between them. Moreover, when you integrate native species into your arrangement, you’re also helping showcase our own plant heritage. Plus, you’re preventing the introduction of potentially invasive species.

Advice for promoting biodiversity in the garden

1- Diversify your plant life

The more diversified is the flora in your garden, the more you’re encouraging biodiversity.

• Incorporate different species and sizes of trees, shrubs, perennials and annuals in order to meet the needs of a great variety of organisms.

• Select, as much as possible, native species.

• When choosing plants, be sure not to introduce invasive exotic species!

• To achieve a maximum of biodiversity, it’s recommended that you reproduce the plant strata present in the natural environment. Introducing shrubs and herbaceous plants under or around trees is a good way to reproduce the vertical stratification of forests.

2. Offer an abundant and varied source of food

Trees, shrubs and herbaceous plants are at the base of the food chain. They provide nectar, pollen, fruit, leaves, sap, seeds and nuts for numerous animals.

• Make sure you have plants that flower and fruit continually so that pollinators, birds and small mammals can feed from springtime through to autumn.

• Group flowers of the same species together in small beds rather than scattering them here and there around the flowerbed. Keeping plants together makes things easier for pollinators, who’ll find the pollen and nectar they feed on more readily. And kept together like that, plants will make a better visual impact.

• Promote pollinator activity by placing nectar-producing plants in a sunny spot protected from the wind.

• Be aware that moths are attracted by plants with fragrant flowers, usually white or light-colored, that open in the evening.

• Avoid ornamental cultivars with double or triple flowers. Nectar and pollen are often produced in lesser quantities or are less accessible to pollinators.

3. Create areas where fauna can take shelter and breed

Trees, shrubs, grasses, perennials, piles of stone or wood, underbrush, ground litter and even manmade insect hotels make up shelters and breeding sites for a host of beneficial organisms.

• Most trees and shrubs serve as shelter and nesting sites for birds, but conifers are particularly useful for them to camouflage themselves from predators and protect themselves from the cold. Besides, the seeds contained in conifer cones are food for numerous species in our regions. Native trees and shrubs also play host to insects that local birds typically consume.

• It’s not necessary or even desirable to do a major housecleaning on flowerbeds in the fall, since dried stems and dead leaves provide winter shelter for a number of organisms beneficial for the garden. In addition, some birds feed on seeds produced by the plants late in the season. Furthermore, by leaving dead stems and leaves in place, you’re promoting snow cover and thus providing better wintertime protection for plant life. Finally, as it decomposes, that organic matter nourishes both soil and plants.

• Integrate host plants needed by butterflies during their larval stage (e.g., milkweed for the monarch caterpillar, parsley for the black swallowtail caterpillar). And of course, you have to not mind having caterpillars around!

4. Install an accessible source of clean water

Open water being rarer in urban environments than in natural ones, it’s essential to provide water points for animals that visit the garden.

• A pond, a stream, a birdbath or just a small container filled with water make it possible for animals to wash and quench their thirst.

• Use shallow or gently sloping structures so that small organisms have easy access to the water. Don’t forget to change the water in birdbaths and containers every day in summer, and to clean them regularly.

• Some butterflies can get the water and minerals they need from muddy surfaces. A patch of damp sand or a mud hole created between flowerbeds can make for an interesting site for observing them.

5. Put the right plant in the right place

By placing the right plant in the right place (based, especially, on the amount of sun and the characteristics of the soil in your garden), you’re ensuring it vigorous growth while using less water and fewer fertilizers.

6. Avoid cultivation methods that unbalance the environment

Systematic use of synthetic fertilizers and/or pesticides often creates more problems than it solves. Interventions should be aimed at preserving the equilibrium of the environment.

• Recycle the organic matter from perennials by letting them decompose in the ground. In most cases you won’t have to add anything else to your flowerbeds. Should it proves necessary to add fertilizer, use either natural ones or compost, which advance biological activity in the soil.

• Remove weeds by hand and use organic mulch to reduce the growth of unwanted plants.

• Take the time to clearly identify the cause of the problem when a plant isn’t doing well. If it’s a question of poor growing conditions, sometimes it’s enough to simply move the plant. If a pest or a disease is the reason, take action only if necessary, and using the control method that has the least effect on the environment. Pesticides, even low impact ones (like insecticidal soap), are not danger-free for beneficial organisms. If you do use pesticides, make sure to abide by the regulations in your municipality.

7. Don’t collect native plants from their natural environment.

Instead, buy plants produced in nurseries.

Picking from a natural environment can lead to a decline in our native flora, in addition to disturbing habitats. Not just that, but plants taken from nature have much more difficulty adapting to their new environment than those produced in nurseries. Don’t hesitate to ask merchants questions to determine where their plants come from.

See also


Add this