Native Plants for Shorelines that Flood

Many cottagers have shorelines that flood in the spring. Discover how to use native plants to make the most of the sogginess.

By Simon Payn

We’re coming up to the time of year I call “mud season”, when the snow melts and the ground is saturated. This year, with the unusual amount of snow we’ve had, could be particularly muddy.

It’s also the time of year when the water in Haliburton’s lakes is at its highest. For some of us, it means our waterfronts become soggy.

It’s easy to see these areas as problematic. I’m here to suggest you embrace the sogginess. While we wouldn’t want water entering our cottage basements, lakeshores that periodically flood are a natural occurrence. The good news is, many plants are adapted to exactly these kind of conditions.

Why plants benefit your shoreline

Plants provide vital food and habitat for wildlife. But apart from that, there are many reasons to have a vegetated shoreline, particularly in areas subject to flooding.

Shoreline plants can help reduce flooding because they slow down the speed water runs off into the lake, allowing it to be absorbed into the ground instead. The water enters the lake more slowly, lessening the potential for flooding.

The vast network of roots plants need to thrive in these conditions have the benefit of stabilizing the shoreline, preventing soil being washed away in high water, from rain or due to the wakes of boats. Using plants to mitigate erosion is often cheaper than using hard materials, particularly as the maintenance costs are much less.

Shoreline vegetation filters runoff before it enters the lake, trapping pollutants and contaminants. This process helps prevent excess nutrients that can lead to excessive aquatic plant growth or algae blooms.

What kinds of plants tolerate fluctuating water levels?

You know what they say: nature abhors a vacuum. That’s why we seldom find places without something growing in them. The same is true of lakes with fluctuating water levels. Some plants are adapted to being saturated at some times and drier at other times.

It’s always good to get ideas from natural areas in the Highlands. If plants are happy in these areas, it’s likely they will be happy at your cottage, too. A lot of these plants have adaptations in their roots that help them thrive in these circumstances.

Plants with rhizomatous root systems, for example, are able to store nutrients for when they are under stress. They’re also able to spread easily, producing new shoots to replace those damaged by too much water. Their spreading roots also make it more likely they can reach the soil where there’s still enough oxygen. These types of roots also help hold the soil together, helping the plant survive and reducing shoreline erosion.

Other plants have deep root systems, allowing them to cope with fluctuating water levels, reaching water when the soil at the surface is dry. These deep anchors also help to plant stay rooted during a flood.

There are also plants with crown-forming root systems, which keep most of the roots above the flood. This allows the plant to recover quickly after high water levels.

Lakeshore plants have several other adaptations that help them thrive. They might have air channels in their roots that transport oxygen during flooding, or they can continue to thrive on lower oxygen levels. Others take advantage of wet periods to put down more roots, while others go dormant when conditions aren’t optimal.

Examples of native plants for Haliburton shorelines

Below are some native plants that might be suitable for your shoreline. However, there are more factors at play that just moisture tolerance, for example: the amount of sun or shade, how wet the area actually is. If we come to look at your shoreline, we will assess it so we can recommend exactly the kind of plants that would thrive there.

Trees

Tamarack (Larix laricina) – Deciduous conifer reaching 15-25 m tall. Features soft, needle-like leaves in clusters, turning golden before dropping in fall. Shallow, wide-spreading root system adapted to wet conditions and seasonal flooding.

Pussy Willow (Salix discolor) – Deciduous shrub or small tree reaching 3-6 m tall. Features elliptical leaves and distinctive fuzzy catkins (pussy willows) appearing in very early spring before leaves. Moderately deep roots specifically adapted to shorelines with seasonal flooding.

Shrubs

Bog Birch (Betula pumila) – Deciduous shrub growing 1-3 m tall. Features small, rounded leaves and inconspicuous catkins. Bark is smooth and dark brown. Tolerates seasonal flooding and cold temperatures. Shallow, fibrous root system adapted to wet conditions

Red Osier Dogwood (Cornus sericea) – Deciduous shrub growing 1.5-2.5 m tall. Features opposite, oval leaves and flat-topped clusters of white flowers in late spring, followed by white or pale blue berries. Known for bright red stems in winter. Rhizomatous roots. Commonly found naturally in areas with fluctuating water levels.

Kalm’s St. John’s-wort (Hypericum kalmianum) – Compact deciduous to semi-evergreen shrub reaching 60-90 cm tall with narrow blue-green leaves and bright yellow flowers blooming July-September. Native to Great Lakes shorelines. Can handle both flooding and drought conditions.

Winterberry (Ilex verticillata) – Deciduous shrub reaching 2-4 m tall. Features elliptical, toothed leaves and inconspicuous white flowers in early summer, followed by bright red berries persisting into winter. Medium-deep roots adapted to seasonal flooding followed by drier periods.

Sweet Gale (Myrica gale) – Deciduous shrub growing 1-2 m tall. Features aromatic, leathery leaves and inconspicuous catkins in early spring. Rhizomatous roots adapt to water level changes.

Meadow Willow (Salix petiolaris) – Deciduous shrub reaching 2-4 m tall. Features narrow, lance-shaped leaves and slender catkins appearing in early spring. Tolerates seasonal flooding. Fibrous root system with moderate depth adapted to fluctuating conditions.

Meadowsweet (Spiraea alba) – Deciduous shrub reaching 90-150 cm tall. Features narrow, lance-shaped leaves and upright spires of small white flowers blooming in mid to late summer. Rhizomatous root system naturally occurs along shores with fluctuating levels.

Grasses and Sedges

Bebb’s Sedge (Carex bebbii) – Fibrous roots with short rhizomes; high stress tolerance for seasonal drying.

Fox Sedge (Carex vulpinoida) – Clump-forming sedge. Features narrow leaves and dense, fox-tail-like seed heads. Often found in wet meadows, marshes, and along shorelines. Fibrous roots with short rhizomes noted for flood tolerance and adaptation to fluctuating conditions.

Bluejoint Grass (Calamagrostis canadensis) – Cool-season perennial grass forming loose to dense tufts, reaching 60-150 cm tall. Features flat, lax leaves and open, purplish panicles that turn golden in fall. Forms dense rhizomatous network; excellent for soil stabilization during flooding cycles.

Herbaceous Perennials (Forbs)

Silverweed (Argentina anserina) – Low-growing perennial herb spreading by stolons, forming mats up to 10 cm tall. Features compound leaves with silvery undersides and solitary yellow flowers blooming late spring to mid-summer. Useful for erosion control in wet areas. Rhizomatous root system that stabilizes soil in fluctuating conditions.

American Sweet Flag (Acorus americanus) – Perennial wetland plant growing in dense stands, reaching 60-90 cm tall. Features sword-like leaves and a flower spike resembling foliage. Prefers consistently wet or saturated soils and full sun to partial shade. Often found along pond edges, streams, and in marshes. Rhizomatous roots specifically adapted to fluctuating water levels along shorelines.

White Turtlehead (Chelone glabra) – Herbaceous perennial reaching 60-90 cm tall. Features lance-shaped, opposite leaves and clusters of white to pink turtle-head shaped flowers blooming late summer to fall. Fibrous roots with some rhizomatous spread specifically adapted to edges of waterways with seasonal fluctuation.

Common Boneset (Eupatorium perfoliatum) – Herbaceous perennial growing 90-150 cm tall. Features lance-shaped, opposite leaves that join around the stem, and flat-topped clusters of small white flowers blooming late summer to fall. Short rhizomes with fibrous roots; naturally found in flood-prone areas that experience seasonal drying.

Spotted Joe-Pye Weed (Eutrochium maculatum) – Herbaceous perennial growing 1-2 m tall. Features whorled, lance-shaped leaves and large, flat-topped clusters of mauve-pink flowers blooming in late summer to fall. Short rhizomes with fibrous roots adapted to fluctuating conditions.

Common Sneezeweed (Helenium autumnale) – Herbaceous perennial reaching 90-150 cm tall. Features lance-shaped leaves and daisy-like yellow flowers with raised brown centers. Medium-deep roots; specifically noted for flood tolerance in natural habitats.

Harlequin Blueflag (Iris versicolor) – Herbaceous perennial growing 60-90 cm tall. Features sword-like leaves and showy blue-violet flowers with yellow and white markings, blooming in late spring to early summer. Rhizomes can help stabilize soil in wet areas. Rhizomatous root system tolerates both flooding and periodic drying; high stress tolerance.

Cardinal Flower (Lobelia cardinalis) – Herbaceous perennial growing 60-120 cm tall. Features lance-shaped leaves and brilliant red, tubular flowers blooming in late summer to early fall. Crown root system provides stability; high stress tolerance; specifically noted for flood tolerance.

Great Blue Lobelia (Lobelia siphilitica) – Herbaceous perennial reaching 60-90 cm tall. Features lance-shaped leaves and spikes of bright blue, tubular flowers. Crown root system with high stress tolerance; documented flood tolerance in natural habitats.

Square-stemmed Monkeyflower (Mimulus ringens) – Herbaceous perennial growing 30-90 cm tall. Features lance-shaped leaves and snapdragon-like, lavender-blue flowers blooming from mid-summer to early fall. Fibrous roots with some rhizomatous spread; high stress tolerance; naturally occurs in areas with water level changes.

Obedient Plant (Physostegia virginiana) – Herbaceous perennial reaching 60-120 cm tall. Features lance-shaped leaves and spikes of pink to purple tubular flowers that can be positioned along the stem (hence ‘obedient’). Rhizomatous spread; adapts well to changing water levels in natural habitats.

Final thoughts

One of our mantras here at Grounded is to dance with nature rather than fight it. Fluctuating water levels and the sogginess they produce are a fact of life in Cottage Country. We can decide to battle them by forcing the water to stay away, or we can embrace them, using nature itself to mitigate the problem.

Wouldn’t a flourishing shoreline of plants and animals be a lovely way to greet spring?