Choose the right coniferous evergreen for your garden

A few quick tips to help you avoid conifer confusion

Credit: GardenWise

Given time many conifers outgrow their garden space – so knowing how to choose just the right one is crucial

White spruce (Picea glauca)

Coniferous evergreens are a natural choice in northern gardens for several reasons. They are the main component of the sub-boreal forest that surrounds our small patches of cultivated ground, and can visually tie the two areas together, giving our gardens a sense of regional “place,” of belonging in the larger landscape.

The other, and perhaps better, reason for planting them is that they come in a thousand shades of green that provide that all-important winter interest to the snow-blanketed land four months of the year. 

Choosing an evergreen tree in the right size

Norway Spruce
Norway Spruce (Picea abies)

You’d think it would be easy to pick out a few nice evergreens for the backyard, given that there are four (or five or six, depending on where you live) native genera of coniferous evergreens.

The problem becomes apparent when you go out into the woods to dig yourself up a sweet little spruce or fir, and then look up. All of our native trees get huge – pine or spruce, true fir or Douglas fir, these are trees that can hit 30 m (100 ft.) and overwhelm a yard.

There are also dozens of species of non-native conifers that can grow just as big, although these are more likely than our native species to be found as named cultivars in the garden centre. 

There are any number of dwarf, contorted and weeping forms available, to suit every taste and space. These are all cute when they are little, but the cautious gardener (which I am not) will take into account the natural shape of these nursery-grown plants as well as their ultimate size.

Those perfect pyramids may be the result of pruning rather than nature, the graceful spirals developed by an experienced hand, and I don’t even want to talk about those cedars butchered into unnatural shapes that the average homeowner will never be able to maintain.

If you’re not sure if the contours are natural or cultured, a quick look at the tips of the branches should tell you, if the sales staff can’t.

Consider the growth rate of your tree

Pine tree
Pine tree (Pinus sp.)

Ultimate size is the other factor, and the one that always seems to slide by me, resulting in many paths and a fence or two in my one-acre garden having disappeared underneath verdant growth.

Nest spruces billed at growing to 2.4 m (8 ft.) wide will surprise everybody by eventually doing just that, and cute young blue spruces can grow into monsters that eat sidewalks and block out all light to houses.

“Dwarf” and “compact” are relative ­– a dwarf version of a 30-m (100-ft.) tree may mature at 1.5 m (5 ft.) or 23 m (75 ft.). 

Estimating your tree’s growth rate

The industry is moving towards a standard classification system to help buyers comprehend growth rates (see sidebar), but lacking sufficient information on the plant tag or at the garden centre, an educated guess can be made by measuring this year’s (or last year’s) growth.

Stem and foliage should be easy to distinguish from older growth, and it will give you a good indication of how the tree will grow. Conifers will grow roughly the same amount every year for the rest of their long lives.

Conifer Growth Rates

Class Growth Rate
Miniature Less than 8 cm (3 in.) a year

Dwarf 8-15 cm 
 (3-6 in.) a year

Intermediate 15-30 cm 
 (6-12 in.) a year

Large 30 cm (12 in.) plus per year

A leggy pine that has put on a 45-cm (18-in.) leader in one year, or a nest spruce that has grown a scant furry inch, will continue that pattern of growth, given allowances for growing conditions. (Yes, I know, you could prune it faithfully every year – but will you?)

Asking only that they get the occasional watering and fertilizer while becoming established, evergreen conifers are amongst the lowest-maintenance plants available to northern gardeners. They need only enough room to grow into the four-season beauties that they can be.