Planting on a slope

beebalmThe following are common methods used to minimize erosion in sloped gardens. Before deciding which to follow, familiarize yourself with your slope’s conditions (moisture, sun, wind etc.) and choose a planting scheme in response to those conditions.

Do not remove existing vegetation (i.e. grass) from the site until you are ready to plant/hardscape your slope since existing roots are keeping the soil stabilized. If planting a garden over grass, us the sheet mulching method (smother grass with cardboard, compost and mulch) in place of physically removing sod.

Create berms and swales

You can break up the slope by building up areas (berms) or creating depressions (swales). When planting into a slope, build up the soil just below the planting in order for the water to slow and thus percolate into the plant’s root system. Note that any grade changes can negatively affect current root systems (of nearby trees and/or shrubs).

Set stones into the slope

Dig larger stones into the slope and plant alpine/rock garden plants in between. This too will break up the slope therefore decreasing water run-off and erosion. Merely placing stones on the slope causes a potential hazard as soil washes away, dislodging the stone.

Create a terraced slope

Terracing or re-contouring your slope into multi-level flat garden beds (much like large steps) can be created by dividing garden beds with retaining walls. Following the contours of the slope will lend to a more natural effect. Refer to a professional when installing retaining walls.

Varied height planting and mulching

Height variability as well as a mix of woody and herbaceous plants will intercept and slow rainfall, increasing proper water to soil infiltration. Mulch heavily between plants (3”); mulch is incredibly beneficial for it reduces run-off, conserves soil moisture, suppresses weeds, protects plants from winter-injury, prevents wide-fluctuations in soil temperature, and reduces soil splashing which can prevent the spread of some plant diseases.

Planting the right plant in the right space

Place drought tolerant plants at the top of your slope and plants that can thrive in wet soils at the base. As a general rule, water will quickly run through/over the peak of a slope and settle at the base. Select plants that thrive in these conditions for a healthier lower maintenance garden.

Suggested plants for a slope

A great number of plants can be grown in slopes, from large shrubs and trees to low groundcovers. The following are just a few easy to grow suggestions, but we encourage you to be creative in your planting!

Many plants listed in these lists can be very aggressive spreaders, and it is for this very trait that makes them so effective at erosion control. When introducing these plants to your landscape, ensure they will not spread into neighbouring yards, garden beds or turf areas by installing root fences.

Sun

Slope location

botanical
Name

Common
name

Height

Plant type and characteristics

Top-mid

Achillea spp. 

Yarrow

0.6m

Perennial, with red, pink, yellow, orange, white flower
mid-base

Anemone canadensis

Canadian Anemone

30 cm

Perennial groundcover with white spring flowers
Top – mid

Amelanchier stolonifera

Running Juneberry

1.2-1.8m

Native shrub that forms thickets, with edible fruit, white flowers and nice fall colour

Top – base

Aronia melanocarpa

Black Chokeberry

2.4m

Native shrub with white flowers and black fruit

Top – mid

Cerastium tomentosum

Snow-in-Summer

10-25cm

Mat forming perennial with white flowers and silver leaves

Top – mid

Cotoneaster adpressus

Creeping Cotoneaster

40cm

Evergreen shrub with red berries

Mid

Helianthus tuberosus

Sunchoke (sunflower)

1.5-3m

Native perennial with yellow flowers and edible roots

Base

Itea virginiana

Sweetspire

1.8m

Native shrub with white flowers and red fall colour

Top – mid

Juniperus virginiana 

Eastern Red Cedar

10m

Drought tolerant native evergreen

Top – mid

Lavendula angustifolia

Lavender

45cm

Perennial with purple flowers and fragrant foliage

Base

Lobelia cardinalis

Cardinal Flower

30cm

Native perennial. Late summer red flower, riparian.

Mid – base

Mentha spp.

Mint, Spearmint

15-60cm

Perennial with fragrant foliage and purple flowers. Edible.

Top – base

Monarda spp.

Beebalm, Bergamot

30-90cm

Native perennial with red, pink or mauve flowers

Top – base

Myrica pensylvanica

Bayberry

1.8-4m

A versatile native shrub that prefers shade and does well in dry to moist soil

Mid

Oenothera spp. 

Evening Primrose, Sundrops

20-30cm

Native perennial with yellow or pink flowers

Top – mid

Origanum vulgare 

Culinary Oregano

30-45cm

Native perennial with fragrant foliage and purple flowers. Edible.

Top – mid

Panicum virgatum

Switch Grass

0.6-1.5m

Native grass with airy inflorescence, winter interest

Base

Rosa blanda 

Meadow Rose

1-1.25m

Native shrub with showy flowers and very few thorns

Top – mid

Rhus aromatic

Fragrant Sumac

1.5m

Native shrub with fuzzy red berries and nice fall colour

Top – mid

Rhus typhina

Staghorn Sumac

3m

Native, colony forming tree with fall colour

Top – mid

Salvia officinalis

Common Sage

60cm

Drought tolerant perennial with mauve flowers. Edible.

Top – mid

Schizachyrium scoparium

Little Bluestem

1-1.25m

Native grass with brilliant fall colour

Top – mid

Sedum spp.

Stonecrop

10-50cm

Drought tolerant perennial. Various colours.

Top – mid

Stachys byzantine

Lamb’s Ears

30cm

Low growing aromatic perennial groundcover

Top – mid

Thymus spp

Thyme

10cm

Low growing aromatic perennial groundcover

Part shade / shade

Slope location

botanical
Name

Common
name

Height

Plant type and characteristics

Top – base

Cornus racemosa

Grey Dogwood

4m

Native shrub with white berries. Pollinator.
Top – base

Cornus stolonifera

Red Osier Dogwood

4.5m

Native shrub with white flowers. Young twigs are red.
Top – mid

Epimedium spp.

Barrenwort, Bishop’s Hat

15-40cm

Drought tolerant perennial groundcover

Top – mid

Euonymus fortunei

Wintercreeper

1.2m

Spreading woody evergreen shrub

Top – mid

Gallium odoratum

Sweet Woodruff

20cm

Perennial groundcover with small white flowers

Top – mid

Geranium macrorrhizum

Big Root Cranesbill

30-60cm

Perennial with pink flowers and fragrant leaves

Top – mid

Geranium sanguineum 

Bloody Cranesbill

35cm

Perennial with bright pink flowers and nice fall colour

Mid

Hamamelis virginiana 

Witch-hazel

3.6m

Native shrub with yellow blooms very early spring

Top – mid

Hydrangea spp. 

Hydrangea

varies

Drought tolerant shrub with showy white flowers

Top – mid

Lamium spp.

Deadnettle

25cm

Perennial with purple, white or yellow flowers

Base

Matteuccia struthiopteris

Ostrich Fern

1.5m

Large fern with edible fiddleheads. Native perennial.

Mid

Myrrhis odorata

Sweet Cicely

80cm

Perennial with white flowers and anise flavoured seeds

Base

Onoclea sensibilis 

Sensitive Fern

30-60cm

Native perennial. Chartreuse coloured fern.

Top – base

Parthenocissus vitacea

Virginia creeper

varies

Versatile vine that likes sun or shade. Nice fall colour.

Mid

Phlox stolonifera 

Creeping Phlox

10-30cm

Perennial with purple flowers

Mid – base

Physostegia virginiana

Obedient Plant

45-90cm

Perennial with white or mauve flowers late summer

Mid- base

Polemonium reptans

Jacob’s Ladder

30-45cm

Native perennial with purple, pink or white flowers

Mid

Polygonatum spp.

Solomon’s Seal

0.9m

Perennial with arching foliage. Some are native.

Mid

Polystichum acrostichoides

Christmas Fern

45cm

Perennial evergreen native fern

Mid

Pulmonaria spp

Lungwort

30cm

Perennial with spotted leaves and purple to pink flowers

Top – mid

Sorbaria sorbifolia

False spirea

1.5m

Shrub with white flowers. Readily suckers.

Mid – base

Symphoricarpos alba 

Snowberry

0.9–1.5m

Native shrub with white berries. Attracts birds.

Mid – base

Tiarella cordifolia

Foam Flower

30cm

Native groundcover with fuzzy white flowers

Top – mid

Viola sororia 

Common Blue Violet

25cm

Native perennial groundcover with purple/blue flowers

74 KBPrinter-friendly: Suggested plants for a sunny slope68 KBPrinter-friendly: Suggested plants for a shady or partially-shady slope