Broadleaf Evergreen Groundcovers

Description:

Groundcovers can grow in a variety of forms and sizes and may be grasses, vines, perennials or shrubs. Typically a ground cover will cover the earth with dense, low growing foliage that has the ability to prevent the germination and growth of weeds.

Broadleaf evergreen groundcovers maintain their leaves throughout the seasons providing year round visual interest through form, colour and texture.

This fact sheets provides introductory information about growing broadleaf evergreen groundcovers.

Uses:

The beauty of evergreen groundcovers is in their year round interest. Because of their varied shape, texture and size they can be used to meet many design interests.

Broadleaf evergreen groundcovers can be used as an ideal foundation planting. Many will allow spring bulbs to grow through them. Many tolerate shady conditions and grow where grass will fail to thrive. They can be used to minimize work when the goal is to establish a low maintenance landscape and eliminate the need for grass cutting or weeding.

Their practical uses include cooling the soil, reducing water requirements, stabilizing soils, preventing erosion and reducing weed growth. In addition, they can act as a habitat and food source for birds.

Location:

Broadleaf evergreen groundcovers can grow in a wide variety of growing conditions from deep shade to bright sunlight, in poor, sandy or fertile soils rich in organic content.

Ground covers often spread quickly. They should be planted where their spreading habit and their ability to reduce water loss and soil erosion is welcomed (e.g. on steep slopes).

Considerations Related to Choice:

There are a number of considerations when choosing evergreen groundcovers. Choose a plant that will thrive in your growing conditions. Consider hardiness, as well as sun/ shade conditions, soil (texture, structure and soil pH), and moisture availability.

Consider how the groundcover will relate to its surroundings through all seasons. Will your chosen plant provide 'visual balance' when positioned in your garden? Remember that evergreen groundcovers will stay green year round.

Choice is personal. They can be chosen to meet your aesthetic requirements (height, width, texture, form, colour, winter interest). You may also wish to consider growth rate as well as blooming season or fall colour. Walk through a greenhouse, visit public gardens, and look at the neighbours' gardens. Once you know what's available you can start refining your decision.

Cultural Conditions/Planting Requirements:

Soil

Well-drained soil is required for growing most plants; well-drained means that water will drain through easily. When preparing a new garden consider a soil mix of 3 parts soil, 2 parts organic matter/compost/ peat moss, and 1 part sand. This mix will enable good drainage, ensuring that surface water will not puddle or drain through so quickly the soil dries out in a few hours.

Consider testing your soil to understand soil nutrient levels and pH (i.e. level of acidity or alkalinity). Having this information is key to choosing the appropriate additives. If your soil requires more nutrients consider organic additives such as compost. Adding lime to the soil will make the soil more alkaline, while mulching with such organic materials such as pine needles or shredded oak leaves will make the soil more acidic.

Adding organic matter each year to the soil, will improve the structure of the soil (enhancing nutrient availability, and water retention and, as well, improving drainage.

Always check the preferred soil conditions and nutritional requirements for your chosen species/variety.

Air circulation

Plants benefit from good air circulation. If plantings become too dense there is a chance that reduced airflow will enable the spread of disease and pests.

Groundcovers need to be properly spaced. Before planting always check planting instructions and consider the estimated mature width of the plants.

Water

Water thoroughly when you plant. Continue to water regularly to enable the plant to become established. Once established, the frequency of watering can be reduced. Note that it may take a couple of years before plants are fully established.

It is essential to water deeply enough to ensure that the soil is wet at least one inch below the surface. Without adequate moisture young plants might perish, or, at the very least, not thrive.

Mulching around plants using shredded leaves, shredded bark or compost, will enhance moisture retention and reduce weed growth.

Gardeners often choose groundcovers because of their low maintenance. If they are planted in the right places, pruning can be minimized.

Maintenance:

Many can often survive adverse growing conditions. Once established they require minimal maintenance.

Diseases and Pests:

Providing that they are hardy and planted in appropriate growing conditions, once established, broadleaf evergreen groundcovers are generally long lived.

While attacks by pests and disease are infrequent, both pachysandra and euonymus are susceptible to scale infestation and should be carefully monitored.

Organic Management/Control Strategies:

The City of Toronto adopted a new municipal by-law (spring 2004) that restricts the use of pesticides. For details about the by-law visit the Pesticide by-law page on Toronto Public Health's Web site at www.city.toronto.on.ca/pesticides or www.toronto.ca/health. Questions may be e-mailed to pesticide@toronto.ca.

As a general rule, good cultural practices that encourage optimal growing conditions and good air circulation should minimize the risk of disease. Healthy plants, grown in appropriate conditions, are less stressed and less vulnerable.

Use only clean garden tools.
Maintain a chemical free garden that will promote natural predators.
Plant disease resistant cultivars.
Plant other plant species that attract a variety of insects to the garden. For example, a light infestation of scale insects can be kept in check by birds and beneficial insects.
Avoid overhead irrigation methods late in the day as they encourage fungal diseases.
Rake up and destroy all diseased parts of plants and debris. Do not use this organic material as compost.
Use mechanical control methods. For example, use a strong jet of water to knock off aphids, or spray plants with water mixed with a small amount of liquid hand soap.
Visit your garden centre to purchase natural predators or parasites to control pests (e.g. diatomaceous earth for aphid and earwig control; Steinernema carpocapsae (microscopic nematode) will parasitize earwig larvae.)

Recommended Species:

A number of the most popular broadleaf evergreen groundcovers are described below:

Vinca minor (Periwinkle)

is one of the most popular and widely used evergreen ground covers. Periwinkle, also known as Trailing Myrtle, Dwarf Periwinkle and Creeping Myrtle is noted for its dark green, shiny leaves and periwinkle blue flowers. Trailing stems with smooth, evergreen leaves (to 1.5" long) root at the nodes as they grow along the ground and spread to form an attractive ground cover. Tubular, lavender blue, phlox-like flowers (to 1 inch across) appear in the leaf axils in spring and continue to flower intermittently to frost. Foliage will mound up to 6" tall and will spread from 1 to 3 feet.

Periwinkle is used as a versatile ground cover providing good cover for bulb beds. It is easily grown in dry or moist, well-drained soils in full sun to shade. This species will tolerate full shade but will flower less. Plant 12-18" apart to cover large areas. Mulching after planting will encourage it to become established quickly. Vinca Major has a larger leaf and flower.

Pachysandra terminalis

is also known by its common name Japanese Spurge. Japanese Spurge is the most widely planted evergreen groundcover. Pachysandra t. “Silver Edge” is a variegated form of this popular groundcover. It produces creamy white flowers and has dark green foliage narrowly edged in white. This form is slower growing than the all-green form. Pachysandra, will make an evergreen mat about 8" to 10" tall, is hardy in zones 4-8 and will also grow in widely varying conditions from full sun to part shade. Plants form an attractive low patch of shiny dark green and cream leaves, with clusters of white flowers in spring. Pachysandra tolerates poor soil, but prefers a rich organic moist one. Since this plant can be slow to grow, mulching after planting will encourage it to become established faster.

Cotoneaster (Cotoneaster dammeri)

or Bearberry is a low-growing, durable, evergreen shrub that reaches 25 -45cm (1-1 1/2') in height and can spread more than 2m (6') because branches in contact with the soil root freely. This Cotoneaster plant has small, glossy leaves on long trailing shoots with small white flowers that emerge in late spring, followed by red berries. It will thrive in full sun to partial shade, in well-drained soils and is ideal for planting on slopes. This species is drought tolerant once established. Pinching growth tips in spring for the first couple of years will help to encourage an especially dense habit. Prune out any dead branches when noticed. In cold winter regions the leaves sometimes drop in late winter but are replaced by new ones. Note that while this Cotoneaster is evergreen, other Cotoneasters are deciduous such as C.apiculatus and C.franchetti.

Euonymus,

both green and variegated, are excellent broadleaf groundcovers. Euonymus fortunei 'Coloratus', also known as Wintercreeper and Wintercreeper Eunonymus, is a dense, woody-stemmed, broadleaf evergreen plant that comes in a variety of forms. This plant produces lustrous, ovate to elliptic, dark green leaves (1-2" long) that turn dark purple in fall and winter. Purple Wintercreepers have inconspicuous, greenish-white flowers that may appear in June, followed by pink capsules with orange seeds.

It is primarily a trailing ground cover form that typically grows to 6-9" tall, spreading indefinitely and quickly by rooting stems to form a sprawling, tangled, bushy mat. It is similar in habit to English ivy, in that it spreads along the ground, rooting as it goes, until it reaches a vertical surface and begins to climb. If allowed to climb a wall, tree or other structure, this plant assumes more vine-like characteristics and is more likely to produce flowers. Euonymus can be a good ground cover for slopes. It can also used for container plantings, massing and erosion control.

This plant grows in full sun to part shade, likes medium well- drained soil and is widely adaptable to a variety of soil conditions. It thrives in Zones 4-9.

Hedera Helix

or English Ivy is an evergreen vine that can also be used as a groundcover in shade or sun providing the soil is kept moist. This plant is hardy to zone 5, has a dense trailing habit with rich dark green lobed leaves and may become invasive in ideal growing conditions.

References

The Toronto Botanical Garden Weston Family Library is an excellent source for horticultural information.

Hole, Lois. Lois Hole's Perennial Favourites. Edmonton, Alberta,Canada: Lone Pine Publishing, 1996.
Ortho Books. All About Ground Covers. Des Moines, Iowa: Meredith Corporation, Ortho Books, 1993
www.rittenhouse.ca/hortmag/Bruce/Performing.
www.fernlea.com/grdcov/pachy.htm

Factsheets are produced by the Toronto Master Gardeners in association with the Toronto Botanical Garden. They provide introductory information about a broad range of horticultural topics and are intended for personal use and study purposes. Should your gardening group or organization wish to use multiple copies we ask that you inform the Toronto Botanical Garden at info@torontobotanicalgarden.ca.

Date revised: April 19, 2006

Toronto Master Gardener Factsheet