When planning a landscape or garden design you should consider including a few shrubs. There are hundreds of shrub species, varieties and forms available for this growing zone. Shrubs are available in many shapes, sizes and characteristics as well as an array of leaf colours. This column is intended to help you sort through the choices to help you decide what is best for your yard or garden.
A shrub is defined as a woody plant that naturally branches at ground level, as opposed to a tree that has a definitive trunk. Shrubs also tend to be smaller than trees and have a shorter life span.
First decide where you would like to place the shrub(s). Shrubs can range in height from only a few centimetres (a groundcover) to many metres tall (up to 40 feet). With the new hybrids available on the market, you can also get dwarf versions of shrubs that will grow to less than one metre or up to three metres tall for species that would have been normally in the range of 6-15 metres tall. These varieties are a great compromise when you are limited in space or need a focal point in the middle of the garden or close to a building. Also check the reference tag or a book to see how wide a shrub will grow to ensure that you have ample space all around. Typically the root system of a shrub is not as large and strong as trees so shrubs can be placed closer to buildings without fear of damaging a foundation.
What features do you want the shrub to have?
Colour: Some species have yellow or dark purple/burgundy leaves all season while others such as Amur maple, cranberry, sumac and burning bush have green leaves during the growing season that turn brilliant red in the autumn. Do some research before-hand to help you decide, as there are often species within the same family with different leaf colours. You can even find species with variegation or mottling on the leaves.
Form: Some species of shrubs are trained or developed to maintain a specific shape. Some will maintain a globular form, others a cylindrical form and some are grafted to have a single trunk and only upper branches so they look like a topiary. Others are trimmed and trained to have certain shapes such as spiral, non tree-like shapes (animal, etc) or look like another specie altogether. Some species are not all that spectacular looking when covered in leaves, but have a fantastic shape and form in the winter months when the leaves have fallen (dogwoods, hazelnuts). Also some shrub varieties have weeping branches for added interest.
Flowers: Almost all tree and shrubs produce flowers, but not all species have flowers that are pretty. There are many shrub species with great showy flowers. Some shrubs bloom in the early spring (lilac; flowering cherry, almond, apple, and fruit shrub species; snowball and other Viburnum species; etc.) while other species flower in the late summer and early fall like the hydrangea species. Flowers on the species listed above can range in size from about the size of your fist to almost the size of a dinner plate and can be white to shades of pink. If it is a flowering shrub that you desire there are many choices.
Deciduous or evergreen: Shrubs come in both deciduous and evergreen species. Most of the deciduous species are broad-leafed with exception of tamarisk and tamarack shrub varieties but many evergreen species exist with needles or broad leaves. Examples of evergreen shrubs with needles are junipers, cedar, dwarf Alberta spruce, Mugo pine, etc. Some evergreen shrubs with broad leaves include boxwood (some are now for zone 4), azaleas, rhododendrons, bearberry, bog rosemary, holly family, etc.
As you can see from this column about shrubs, there are a lot of decisions to make when choosing a shrub for your landscape. This column provides a quick overview of what to consider but taking some time to research the internet or some good books on shrubs, will help you learn more about what shrubs have to offer and how they can enhance your landscape.