― D Everett, The Columbian Orator, 1797
I learned to love trees first from my mother and later from the foresters I've come to know in Northwestern Ontario. The passion of tree developers like Rick Durand of Bylands Nursery in BC have also inspired me to value trees. A well-tended tree may well grow to be the soul of a garden.
Lest you think this will be a wholly poetic post, let's shift gears and talk about trees that can withstand the harsh weather of a northern garden. Happily, there are many species that will give us shade, form and privacy.
Could you grow a bur oak in your yard? Absolutely! As a specimen tree that gives shade and character in the urban landscape, I think it is a fine choice.
Bur oak (also spelled burr oak) is a small to medium sized deciduous tree that can grow 15 to 20 m (50 to 65 ft) tall. It is considered a slow-growing tree, but once established it will adapt to dry and moist conditions. As the Manitoba Forestry Association explain in the Think Trees seedling catalogue, "A deep & wide-spreading root system with a strong taproot makes this species drought-tolerant." This makes bur oak a good choice if you are establishing a moisture-conserving landscape.
Remember that 'sense of place' I mentioned? Bur oak is very long-lived, surviving up to 200 years, given care and good growing conditions. There is no doubt a bur oak is a heritage tree worth planting for future generations.
Oaks are divided into two groups: red and white, based largely on the appearance of the leaves and acorns. Bur oak belongs to the white oak family with the characteristic lobed leaf shape. The leaves have a paler underside that is covered with short fine hairs. Leaves turn a tawny brown in fall.
Like other white oaks, the acorns of the bur oak mature in one year. In fact, it's the bur oak acorn that is especially distinctive. The fringed acorn caps give this tree its other name – mossy-cup oak.
We planted a bur oak some years ago. Now, about five years on, it is developing the gnarly branches that give this tree its character.
So let's summarize ...
Size: 15 to 30 m tall, trunk 60-120 cm diam
Moisture: Tolerates a wide variety of moisture conditions
Exposure: Prefers full sun, but can tolerate moderate shade
Soil: Can grow in a variety of soils
Form: Short trunk with a wide crown when open grown
Bark: Thick, dark grey bark, deeply furrowed
For reliable tree planting tips check out the Ministry of Natural Resources' Climate Change pages.
Read more about 'That Tree' iPhone Photo Project
Open grown specimen, Calgary - Flora and Fauna [blog]
Leaves, acorns, branches - Peter M. Dziuk at Minnesota Wildflowers
Fall leaves - The Dirt Doctor