Container Planting

(Question)

A generator pipe is an unsightly item visible on our terrace.
We would like to make it less visible. Would large cedars be suitable for container planting? Where would you source a container big enough to house a cedar. Will cedars overwinter ok? Do you have other suggestions re large enough plantings in containers for our project? Thanks a lot.

 

(Answer)

One, or a group of, container plantings along the low wall would be a lovely addition to your terrace and would provide interest and screening through all seasons.  The rule of thumb for winter hardiness in containers is that the plants you choose should be hardy to two zones lower than our own, which in Toronto would be Zone 4, or to be safer, Zone 3.

Cedars, for example the ubiquitous Thuja occidentalis ‘Smaragd’ or Emerald Cedar are popular choices for containers, but because this variety requires significant moisture they can be challenging to keep in good shape over time.  This is particularly true of plantings in containers on balconies which contend with wind and winter dryness.  Cedars in general stand a good chance of overwintering in a container, with good care.  This Toronto Master Gardeners  post, in response to a question about overwintering in containers, provides some good advice:  http://www.torontomastergardeners.ca/wp-admin/post.php?post=19274&action=edit

Another Toronto Master Gardeners post quotes well-known garden writer Art Drysdale’s book, “Gardening Off the Ground” in which he recommends that containers for evergreens such as Emerald Cedar should have a minimum soil depth of 30 cm/12 in with 40 cm/16 in desirable.  http://www.torontomastergardeners.ca/wp-admin/post.php?post=14651&action=edit

Here are some specific recommendations, again from Art Drysdale, as to the varieties of evergreens for container plantings that will overwinter: http://www.icangarden.com/document.cfm?task=viewdetail&itemid=7759

In terms of other plants, you might consider some of the tall very hardy grasses or bamboo varieties, some of which are invasive and can run rampant in the garden, but can be controlled in a container planting.

This is a lot of reading, but all the posts above provide useful information, not only about evergreens you might consider, but about watering, plant health and overwintering.  The best time for planting evergreens in containers is coming up in May and early June, so it is great that you are thinking about this now.  It is well worth paying a visit to some of the larger nurseries around Toronto which will have a good selection of evergreens and grasses from which to choose.  Pay attention to the hardiness zone when you are looking at plant labels, as this is perhaps the most important consideration, and remember that container trees and shrubs do not grow as tall as their labels suggest.  Larger nurseries also sell containers and can help you choose the right one in terms of size, weight, and material for your terrace.   You can find a list of nurseries around the GTA on the Landscape Ontario website: https://landscapeontario.com/garden-centres/chapter/toronto