Broadleaf Evergreen Groundcovers: A Toronto Master Gardeners Guide

 

Euonymus or wintercreeper comes in green and variegated forms. Some produce attractive red berries in pink cases. (Photo: Helen Battersby)

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 which inhibits 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 gardening guide 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.

Pachysandra terminalis is mostly chosen for its foliage. In spring, however, it can make small clusters of fragrant flowers. (Photo: Helen Battersby)

Cultural Conditions / Planting Requirements

Soil

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 surface, 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.

Maintenance

Many groundcovers can survive adverse growing conditions. Once established they require minimal maintenance. Gardeners often choose groundcovers because of their low maintenance. If they are planted in the right places, pruning can be minimized.

The arching branches of Cotoneaster are decorated in spring with small white or pink flowers, which become brightly coloured berries that can persist into winter. (Photo: Helen Battersby)

Diseases and Pests

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

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

Organic Management/Control Strategies

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:

Arctostaphylos uvaursi, also called bearberry, or Kinnikinick, this is the only native evergreen groundcover on the list. It is found in every province and territory in Canada. With an average height of 15cm and a spread of up to 60cm, Kinnikinick features clusters of pale pink or creamy white flowers in May and June, with small red fruit afterwards. It prefers acidic, sandy soil and full sun to part shade. Hardy to Zone 2. Drought tolerant once established.

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.

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 part sun to full 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.

Cautionary Note:  Although Hedera helix (English Ivy) and Vinca minor (Periwinkle or Creeping Myrtle) have both been popular evergreen ground covers in the past, they are listed on the Ontario Invasive Species list and should NOT be planted.

 

References

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

http://www.fernlea.com/groundcovers/pachysandra.html

Date revised: January 2012

For printable version, click Broadleaf Evergreen Groundcovers- A Toronto Master Gardeners Guide

Produced by the Toronto Master Gardeners, these Gardening Guides provide introductory information on a variety of gardening topics.

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