Columnar Swedish aspen

The Swedish Aspen (Populus tremula) is found throughout northern and western Europe. It is a beautiful species that has light colored bark and some of the best autumn color of any species, with gold being usual but also ranging through oranges and scarlet. It is not grown frequently, but has been used in the production of newer hybrids and cultivars. 

Whenever someone says “I need a tree for privacy”, they almost always want the columnar form of the Swedish aspen. If you drive into any neighborhood on the Canadian prairies, you will probably see this tree. It is often used along fencelines or driveways, or in strict columns around parking lots. You will see them in settings that are often entirely inappropriate for them and they're usually planted too closely together for the trees to be healthy. This form of the aspen is overused to the point that we no longer recommend planting it. There are better options for most people.

Where did this Swedish aspen come from and how did it find itself planted everywhere? Well, it did in fact, actually begin in Sweden. The columnar Swedish aspen (Populus tremula ‘Erecta’) was discovered in the wild in the 1920’s but didn’t really achieve any popularity until the late eighties. It grows about 40 ft. tall and 5-7 ft. wide, sometimes (but definitely not always) turning yellow-gold in the fall. Due to its extremely rapid growth rate and adaptability to a very wide variety of sites and soils, it has become overused for use as screens, hedges, and windbreaks.

The quick growth rate of this tree is an indicator that it also has a short lifespan, with many of the trees planted in the 80s now nearing the end and requiring expensive removal. Other drawbacks of the tree include that it offers no flowers that provide nectar or pollen for insects, it offers no seeds or berries as food for wildlife, it provides little if any cover in the winter, and it will sucker extensively if its roots are disturbed. Fall color is inconsistent and the leaves are not particularly showy.

To make matters worse, any time you have an over abundance of any one species, something is going to come along to try and take advantage of that item as a food source or host. Such is the case with the newly discovered bronze-leaf disease, a fungal pathogen which in recent years has started infecting and killing Swedish columnar aspens. It is also prone to infestation from leaf roller caterpillars, particularly in neighborhoods where it is overused.

If a narrow or columnar tree is required, there are columnar forms of pine, juniper, mountain ash, caragana, saskatoon berry, flowering crabapple (the Spires series is columnar), and spruce that are available at any garden center. They are slower growing than the aspen, but often much better choices in terms of contributing to a landscape.