Oak

Posted by shane - December 23, 2014 - A-Z Plant Maintenance, Trees - No Comments

Quercus macrocarpa (Bur oak)

Quercus ellipsoidalis ‘Bailskies’ (Northern Pin Oak)

Quercus rubra borealis (Northern Red Oak)

Bur oak leaves

We do not commonly see oak trees in the landscape, which is too bad, because they are very beautiful shade trees.  I have only worked on a handful of bur oaks in residential yards.  They are generally thought to be slow-growing, which probably makes them unfavourable, as most people I meet are looking for fast-growing trees and quick privacy.  I think the growth rate of oak depends more on the depth and quality of soil, quality of planting, and level of post-planting care, than it does on the species itself.  I encourage people to plant oak trees.  They are tough and long-lived, and have very attractive foliage, interesting bark, and some varieties have stunning fall colour.

Recently, we planted northern pin oak and northern red oak in a trial on a farm at Mirror, AB. Last year they both made it though a low of -47oC, and the pin oak put on 10″ of new growth last season.  I regard that as a prairie hardy tree.  We will follow the growth of these varieties for the next several years, but have already started including norther pin oak in landscape designs.  It has excellent reddish fall colour, which is something we could use more of in the landscape.

Northern pin oak.

Northern pin oak leaves

In the past few years I have noticed that many bur oaks, particularly those in stressed environments such as boulevards and commercial areas, are afflicted with oak leaf blister and various leaf galls.  I spoke with a well-known entomologist who assures me that these problems are merely esthetic and will not harm the tree.

 

 

Exposure

Full Sun

Pruning Time

Late fall to mid-spring, prior to bud bud break

Pruning

Prune as a central leader standard, with one dominant trunk, and well-spaced lateral branches. As the tree grows, clear the trunk to 5-6′, depending on the location of the tree.  Subordinate co-dominant leaders, if required.  Regular maintenance should consist of removing dead, diseased, and damaged branches.  Remove severely crossing branches and those growing back toward the main trunk.  Oaks require very little pruning and are one of the lowest-maintenance trees.

Crown Reduction and Shaping

Not recommended.  Plant oaks where they will have room to grow to their mature height and width.

(c) 2014 Shane LePage, Wild Rose Garden & Tree Service Inc., Red Deer, AB