Keystone Plants Shrubs Ecoregion 5

Author: Penka Matanska, Master Gardeners of Ottawa-Carleton; published with permission.

“Restoring viable habitat within the humandominated landscapes that separate habitat fragments – with as much of this land as possible – is the single most effective thing we can do to stop the steady drain of species from our local ecosystems.”

Douglas W. Tallamy

For a long time, paved spaces and vast fields of grass have replaced the native plants that insects and animals typically use as host plants or as food sources. Pollination is an essential process in a plant’s life cycle, so introducing plants for bees, butterflies, and moths in our gardens will help reverse the sharp decline in native pollinator populations. In his book Bringing Nature Home, Douglas Tallamy emphasizes our chance to restore the biodiversity balance that has been eliminated in our suburban living spaces. Native plants are well suited to a particular ecosystem region since they have evolved to thrive there. As a result, they are far less difficult to grow.

The Ottawa region falls into the Northern Forest Ecoregion 5. This article, part 3 in a series on native keystone plants, will identify three keystone shrubs for Ecoregion 5. Some of these plants are relatively small and can be easily grown in the limited space of city gardens. They will also help us see more bees and birds in our backyards. Note: The map Ecoregions of North America, level I, was used to determine the ecoregion for the keystone plant articles. This is a large-scale map, and boundaries are not always clear or clean.

What are Keystone Plants?

Keystone plant species are native plants that have the maximum benefits of supporting life by supplying large amounts of food and shelter. They support the specific wildlife that lives in a particular area. These often-ignored species are the backbone of local ecosystems. They are better adapted to the climate and soil conditions of the area and are naturally more resistant to pests. These plants require less maintenance and less additional watering. They provide caterpillars, bees, birds, insects, and other wildlife with nesting places and food, whereas other introduced plants fail to do so.

Vaccinium

Vaccinium is a common and widespread genus of shrubs, or dwarf shrubs in the Heath family. The fruits of many species are eaten by humans. Many are the host for 276 caterpillar species, and 6 bee species rely on these plants for food.

An example is the low-bush blueberry (Vaccinium angustifolium), a small shrub up to 0.5 m in height that is native to eastern Canada and the northeast United States. It forms dense colonies in the wild in both deciduous and evergreen forests. It prefers loose, acidic soils, growing along sandy riverbanks or in meadows and mixed forests. In an urban setting, it can be planted in a sunny or semi-shade location where the soil can be amended with sand. Pinkish-white, bell-shaped flowers clustered along its stems appear in early spring. The fruits are small purple berries that are very sweet and are favored by many birds, including robins, eastern bluebirds, tanagers, and mammals such as red squirrels and chipmunks. The foliage and flowers are also grazed by some animals. Pollination by insects is essential for fruit development. Bees collect nectar, and bumble bees collect pollen from the plants. The low-bush blueberry can be propagated using cuttings and transplanted rhizomes. In fall, the leaves turn bright red and create a focal point in the garden in later months of the year, making the low-bush blueberry a good candidate to grow in your backyard.

Viburnum

The large cranberry (Viburnum macrocarpon) is a small shrub that reaches only about 15 cm in height. It brings flowers, fruit, and fall colour to the garden, as well as a food source and hiding space for smaller insects, caterpillars, and birds. It grows well in full sun or partial shade and in moist, well-drained, acidic soil. Cranberry shrubs can do well layered in the city garden under bigger bushes or trees if exposed to some sunlight. They spread via rhizomes, forming low ground mats when located in cool, moist soil, usually under a tree close to water or in bog areas. The flowers are white to pinkish, with a lily shape growing on long stalks. The red, round fruits ripening in late fall persist through winter and are loved by birds and squirrels. The leaves turn a purple-toned bronze in the fall.

Salis

Salix are native willow bushes that support 397 caterpillar species as host plants and provide food for 12 bee species.

While pussywillow (Salix discolor) and black willow (S. nigra) are larger species suitable for spacious gardens near water, prairie willows (S. humilis) are smaller leafy shrubs that can grow around 3 metres in height. The first two grow in wetlands and prefer moist soils, while the prairie willow prefers drier sandy or gravel soils, identifying it as the only willow that does not grow around water. This makes it very suitable for suburban areas. Planted in full sun to partial shade and trimmed to look aesthetically fitting in the space, the prairie willow not only adds interest, but it will provide food and shelter for wildlife and help the ecosystem balance in your garden. This plant has very distinct leaves with a woolly appearance underneath, which is one of its key characteristics.

Willows bloom in April–May, and the bushes are covered in catkins before the leaves emerge. Since the plants are dioecious, the male and female catkins are formed on different plants. Depending on which type you have, they are hairy round yellow for the male flowers, while the female flowers are slender and more gray-green. The flowers attract bees, and flies feed on the pollen. Other insects, like butterflies and caterpillars, feed on the foliage and stems. Birds use willow branches for nesting and catkins for food in early spring when other food sources are difficult to find.

Benefits of Shrubs

Shrubs diversify the garden with extra depth in horizontal and vertical directions. When choosing bushes for your next garden project, consider the keystone species first. Looking to reintroduce these bushes in your garden will be your small contribution that will have the big impact of helping sustain our eco-diversity in residential areas.