There are a thousand and one good reasons to plant a tree (they clean the air, prevent erosion, create refreshing shade, etc.), but only one not to: lack of space! City lots, by definition, are small and nowadays, even suburban lots are more and more limited in size. Should we therefore stop planting trees? Of course not! And there is even a category of trees that is well suited for use in narrow areas: columnar trees.
Also called fastigiate trees, they don’t grow the way a tree normally would in the wild. The original species would probably have the rather rounded habit and spreading branches typical of your average tree. But occasional mutations occur that result in specimens with branches that, rather than stretching out more or less horizontally, grow upright, forming an acute angle to the trunk. This results in a very narrow habit and therefore a tree that can grow without difficulty in small spaces.
When such mutations are noticed by attentive horticulturists, they can be multiplied on a large scale and thus become readily available in nurseries.
Here are some examples:
Parkland Pillar® Japanese White Birch
(Betula platyphylla ‘Jefpark’)
This birch combines very white bark with a very narrow habit. In addition, the foliage, dark green in the summer, becomes a beautiful yellow in the fall. It grows rapidly and reaches about 30 feet (10 m) in height, but only 6 feet (2 m) in diameter. It’s fairly resistant to bronze birch borer and seems completely resistant to Japanese beetles, unlike North American and European white birches. Plant it in full sun or partial shade in moderately moist soil. Hardiness zones: 2a to 7.
There are quite a few ornamental crabapples with a columnar habit. That means you can pretty much pick any combination of features – white, pink or red flowers, green or purple leaves, red, green or yellow fruit – and expect to find a match or two on the market. And there are columnar fruiting apples, too, that is, with large, edible fruits, for those who want to create a small urban orchard. Here are some varieties among the dozens that are available:
Malus ‘Maypole’ produces pink flowers, slightly reddish leaves in spring that turn green in summer and purple in fall, and small red fruits. M. baccata ‘Erecta’ (‘Columnaris’) is an old variety very easy to find in nurseries. It produces pinkish buds, white flowers and small yellow-red fruits over green leaves. M. ‘Gladiator’ (M. × adstringens ‘Durleo’) produces dark purple leaves, pink flowers and purple red berries. It’s extremely hardy (zone 2). And ‘Northpole’ is a fruiting variety, offering white flowers followed by red apples of good size that taste much like ‘McIntosh’ apples.
Columnar crabapple and apple trees are relatively short (rarely more than 13 to 16 feet/4 or 5 m) and most are hardy in zones 3 or 4 to 8. Their shape ranges from extremely narrow to tightly oval.
Pyramidal European Hornbeam
(Carpinus betula ‘Fastigiata’)
With a rigorously upright and dense habit and attractive ribbed and toothed dark green leaves, this tree is widely used in Europe for tall hedges and windbreaks, but also grows fine on its own. It is marcescent, that is to say that after its leaves turn bright yellow in the fall, they don’t all fall off. Instead, many, now beige, hang on all winter, ensuring extra good density. They do fall off come spring as new leaves come in. For well-drained soils in sun or partial shade. Dimensions: 30 feet x 20 feet (10 m x 7 m). Hardiness zones: 5 to 8.
Upright English Oak
(Quercus robur ‘Fastigiata’)
Very popular, this oak has dark green leaves with rounded lobes and a very short petiole. As with the pyramidal European hornbeam, it is marcescent and its leaves turn brown in the fall, but don’t all fall off, ensuring some winter interest. For full sun in well-drained soil. It’s a very tall tree: 50–60 feet x 10–20 feet (15–18 m x 3–6 m). The cultivar ‘Skyrocket’ is even narrower. Zone 4 b to 8.
There are several other pyramidal and columnar oaks. Ask about them at your favorite nursery.
(Cupressus sempervirens ‘Stricta’)
No, this is not a good choice for cold-climate gardens, but it is the “original” columnar tree, grown for over 2,000 years and, indeed, spread throughout the Mediterranean region by the ancient Romans. It’s the tall, narrow, upright conifer that you see everywhere in Tuscany and Provence and in cemeteries in mild climates the world over. Like most coniferous trees, it remains green all year long and is said to live up to 1000 years, although it remains very narrow, even at full maturity. That said, in home gardens it’s typically pruned occasionally to maintain an even narrower shape. There are also some extra narrow cultivars, like ‘Totem’. For full sun and well-drained soils. It’s a big one: 50–65 feet x 6 feet (15–20 m x 2 m)! Hardiness zones 7 to 10.
Weeping White Spruce
(Picea glauca ‘Pendula’)
Most weeping trees have a very wide habit, often broader than tall, but this tree is an exception to the rule. Its main stem is perfectly upright, but none of its secondary branches seem to have any tonicity, dripping down like a wet rag. So, although it grows taller and taller over time, it never becomes much wider. Its needles are numerous and dense, dark green with a whitish tinge. They keep their coloration all winter. Full sun in a moist, well-drained soil is ideal. Best adapted to cooler climates. 50–65 feet x 5–8 feet (16–20 m x 1.5-2.5 m). Hardiness zone: 2 to 6.
(Populus × canescens ‘Tower’)
Although the Lombardy poplar (Populus nigra ‘Italica’) is probably the most widely cultivated columnar tree in the world, is too prone to diseases for it to be a good choice as an urban tree. That’s where the Tower poplar steps in. It certainly looks like a Lombardy poplar, but is much less sensitive to fungi and bacteria. Since it’s a male plant, it won’t produce unsightly “white fluff” in the spring, a trait common on other poplars. Its habit is very narrow and it bears dark green leaves in the summer that turn bright yellow in the fall. For full sun and somewhat moist soil. 40 feet x 10 feet (12 m x 3 m). Hardiness zone: 2 to 6.
‘Prairie Sky’ poplar (P. × canadensis ‘Prairie Sky’) is similar, but with even better disease resistance. Its distribution is spotty, but it’s a great choice where it’s available.
Columnar Swedish Aspen
(Populus tremula ‘Erecta’)
An even narrower poplar than ‘Tower’, with green-white bark and leaves that shake in the slightest breeze. Certainly, the most attractive of the upright poplars. It’s said to be less likely so sucker than other poplars, but if you damage its roots, it will produce offsets by the dozens! It too is male plant, so will produce no fluff. Full sun, well-drained soil. 50–65 feet x 10–13 feet (15–20 m x 3–4 m). Zone 2b to 5.
Obviously, the columnar trees described above are just a glimpse of those on the market. Visit a nursery specializing in trees and you’ll discover many other narrowly upright trees; certainly one that will catch your eye!