Description of Choosing the Right Tree or Shrub fields

The guide provides a range of information for every species listed. Some of the categories are described below.

Description of the fields

The guide provides a range of information for every species listed. Some of the categories are described below.

Latin, French and English names

The guide identifies trees and shrubs by their most universal and systematic names, which are in Latin. It also provides common names in French and English.

Learn more about Latin names used in botany

Coniferous or deciduous?

The term “conifer” refers to any tree or shrub that has needlelike or scalelike leaves and produces seeds in cones. Deciduous trees, generally defined by opposition to conifers, usually have flat, well developed leaves that they shed in the fall.

Please note that the few herbaceous plants listed in the guide are classified alongside the deciduous species.

Safe planting distance

The safe planting distance indicated for a given plant is based on its maximum height and spread at maturity, a safety margin and risk factors like sensitivity to wind and ice. It is calculated for flat ground and medium-voltage lines.

If your land is sloping, you should adjust the safe planting distance slightly, especially when the planting site is higher than the base of the poles. In such cases, we recommend you increase the safe planting distance by an amount equal to the difference in ground height.

A tree or shrub that is planted at a safe distance may still need to be pruned to clear branches from a medium-voltage line. However, any such pruning would be minimal, if required at all.

Mature size

An illustration shows what the tree or shrub normally looks like at maturity, when it has been allowed to grow freely. In addition, to convey an idea of the plant’s size, a person is shown next to it, along with a distribution line pole in some cases.

For various reasons, like the presence of other plants, shape pruning and weather-related damage, the specimen you plant will probably not have the exact size and shape shown.

The heights and spreads indicated in Choosing the Right Tree or Shrub are based on the maximum growth observed or presumed for Québec; a plant can grow beyond the indicated maximums in ideal conditions. However, more often than not, it is the opposite case: trees and shrubs rarely have optimal conditions for growth. In the case of large trees, for example, the dimensions shown are not reached until 20 or 30 years of growth, or even more.


This section provides general information about the tree or shrub.


It may be relevant to know what family the plant belongs to. Botanists, for instance, can deduce some of a plant’s characteristics from those of related species.

Hardiness zone

Hardiness zones are regions designated by Agriculture Canada according to their climate and, more specifically, their mean minimum temperatures. These zones are used to classify plants by their tolerance to winter cold and identify locations where they will grow satisfactorily.

A lower hardiness zone indicates greater cold tolerance. Consequently, a species’ hardiness zone corresponds to the northernmost area where planting is recommended. For example, a plant with a hardiness zone of 3b can be planted in any zones with an equal or higher number (3b, 4a, 4b, 5a and 5b).

Within a given zone, there may be climate conditions that are more or less favorable. These microclimates may be caused by greater sun exposure or sheltering from the wind, or, on the other hand, a higher wind chill factor.

As a rule, frost is the most harmful factor for vegetation because it harms the plant’s organs while they are still active.

For the hardiness zone of a specific location, refer to Agriculture Canada’s interactive map


The shape gives you an idea how the plant will grow and develop.

As a rule, shrubs have branches that start at the base of the plant, while trees have a bare trunk that supports a crown. However, this description does not always hold true and cannot be systematically applied. Instead, trees and shrubs are more commonly distinguished by their size, even though the exact cutoff point is somewhat arbitrary and varies widely depending on the source.

The following classification criteria are used in Choosing the Right Tree or Shrub:

  • Climber: plant that climbs up a support structure (trellis, pergola, etc.)
  • Creeping shrub and small shrub: a woody plant under 1.5 m tall
  • Shrub: a woody plant from 1.5 m to under 4 m tall
  • Tall shrub: a woody plant from 4 m to under 6 m tall
  • Small tree: a woody plant from 6 m to under 13 m tall
  • Average tree: a woody plant from 13 m to under 20 m tall
  • Large tree: a woody plant that is 20 m tall or more

Light requirements

This information tells you how the plant will react to sunlight. Light tolerance generally rises with age. However, plants that are exposed to the sun too suddenly often have trouble adapting.

Light requirements are broken down as follows:

  • Full sun: over 8 hours of sunlight a day
  • Semi-shade: from 4 to 8 hours of sunlight a day
  • Shade: from 2 to 4 hours of sunlight a day

Growth rate

The indicated growth rate is merely an estimate. In addition, rates are relative and are primarily useful in comparing different species of plants. Clearly, some plants will grow faster or slower than the indicated rate, depending on the environment in which they are planted.


This provides an idea of the plant’s shape and growing habits.

Root system

The root system is an important factor that is not always given sufficient consideration when selecting a tree. For example, plants with strong surface root systems may not be the best choice near a house or patio. However, they are able to survive in shallow soil.

Plants with a deep root system or tap root should be transplanted in plugs of earth or when they are very young to facilitate their recovery. These trees and shrubs grow more satisfactorily in relatively deep soils.

A tree or shrub that suckers profusely may spread quickly, filling an empty space, but can also quickly get out of control.


A maximum of three adjectives are used to describe leaf shapes. An additional comment may provide further details and a little extra information about leafing speed and leaf color in the summer or fall.

The number of leaves that fall in autumn is related to the specimen’s size. Some species also lose their leaves earlier or later than others or over a shorter or longer period, which can affect how long the clean-up is likely to take. However, certain factors, mostly weather-related, also affect the length and timing of leaf drop, making predictions difficult. Conifers may be less of a nuisance, since their leaves (needles) have a 3- to-7-year life cycle and do not drop on a seasonal basis, resulting in a much smaller volume of shed matter.


Four parameters are used to describe a plant’s flowers: type, color, scent and flowering season.


Five parameters describe the plant’s fruit: type, color, volume, season and appeal to animals, especially birds.

Trees that produce significant quantities of fruit can sometimes be a nuisance because the fruit falls to the ground and is crushed, which may require cleaning up. A number of trees are dioecious, meaning that the male and female flowers are found on separate specimens. Since only female trees bear fruit, there are a few points to keep in mind:

  • You can plant a male specimen if you do not want to deal with the disadvantages of fruit, or
  • If you want your tree to bear fruit, you must plant a female specimen and ensure there are male specimens nearby to pollinate it.


Soil may be more or less conducive to a plant’s growth. It is described by six main factors: type, texture, humidity, pH, tolerance to compaction and tolerance to de-icing salt.

Soil type

The plant’s preferences are outlined.

Soil moisture

The plant’s specific moisture preferences are summarized by one or more of the following descriptors:

  • High: the plant can tolerate excesses but would prefer close-to-normal conditions
  • Average: water should be available in sufficient quantities all year long
  • Low: the plant cannot tolerate excess water

Soil texture

The guide specifies the various soil textures in which the plant is able to grow. They are described by the following terms: clayey, loamy, sandy and humus-rich.

Soil texture has a direct impact on drainage and moisture because water seeps quickly into sandy soil, more slowly into loamy soil and quite slowly into clayey soil.

Optimal water availability is usually provided by loamy soil, although other factors like slope, soil depth and water table depth can also have an impact.


The plant’s preferred pH range is indicated, using the following scale:

  • Highly acidic
  • Acidic
  • Slightly acidic
  • Neutral
  • Slightly alkaline
  • Alkaline
  • Highly alkaline

Tolerance to compaction

Tolerance to compaction refers to a plant’s tolerance to recurring pedestrian or machine traffic. This information is provided when available.

Tolerance to de-icing salt/h4>

The plant’s tolerance to the de-icing salt used on roads and driveways in the winter is provided when available.

Maintenance, uses and notes


Some species and varieties benefit from pruning designed to maintain or improve their look or vitality. The proposed pruning guidelines are recommendations, and not in no way obligations.


This category describes the most common uses for a species, which can range from naturalizing developed areas to isolated planting in a yard or garden to showcase one of its decorative features. The list of uses may be rounded out by a comment.


Any information not covered elsewhere is provided here. Examples include optimal sites, sensitivities and other special qualities.

Diseases and insects

Diseases and insects that are most often responsible for dieback or deformations are outlined in this section. Some of these attacks, like Dutch elm disease and bacterial blight, can be exceedingly virulent. The risk of health problems can be high for some of the most vulnerable species. However, there may be certain varieties that offer greater resistance: they are recommended here.

Horticultural varieties

If there exist varieties comparable to the one described, they may be presented here, along with a brief description. Some of these varieties may also be recorded in the tool.