High balcony garden recommendation

(Question)

I have a huge balcony in a downtown condo at the corner of York Street and Queens Quay West in the Harbourfront. It is about 400 square feet, north east exposure, fully exposed to the sky, on the 20th floor of the condo building.

I am looking to turn it into a beautiful garden escape with much greenery … trees, bushes … in planters and large pots, etc.

The issue is the height being on the 20th floor and the wind than can be blow super strong throughout they year. Not to mention the need for the plants selected to survive the frigid, cold winter temperatures we experience annually.

I’d love suggestions on any and tree varieties that will survive well for years in pots and planters. No doubt evergreens will do well, but they can be challenged as they grow through the years. Would be great to have a tree or two up there but I worry about the wind that can howl in fast speeds especially in the winter. By the lake gets pretty frigid.

I’d appreciate any suggestions, if not any professionals I can secure services from.

Thank you in advance.

(Answer)

Thank you for contacting the Toronto Master Gardeners with your question and for providing such helpful photos.

We receive many questions concerning balcony gardening although not too many about planting trees on the 20th floor! Here are some considerations when planting in containers on a balcony:

  • The soil dries out faster on a balcony due to high winds and the simple fact that plants are in containers. The overhang from the next floor also reduces the amount of rain your containers will receive.
  • The hardiness zone for evergreens and perennial plants is lower the higher up you are located. For example, as Toronto has a hardiness zone of 6, plants should be hardy to zone 4.
  • As you want the plants to overwinter, the containers should be large and insulated.
  • The larger and thinner the leaves of a plant, the more they will get damaged by wind. The smaller and thicker, the more they will retain moisture.

The link below gives some basic considerations when planning to plant in containers on a balcony:

https://www.torontomastergardeners.ca/askagardener/balcony-gardening-2/

As for the types of hardy trees and shrubs that would grow well on the 20th floor, some recommendations would be:

  • Japanese juniper (Juniperus chinensis) which needs morning sun and indirect afternoon light
  • Some varieties of Japanese maple (Acer sieboldianum)
  • Cut-leaf lilac (Syringa laciniata), Viburnum (Viburnum), Sambucus Black Lace Sambucus nigra), Kousa dogwood (Cornus kousa)
  • Evergreens such as pines (Pinus), hemlock (Conium maculatum) and dwarf blue spruce (Picea pungens)

The links below also contain some interesting information and advice:

https://www.torontomastergardeners.ca/gardeningguides/pollinator-garden-a-toronto-master-gardeners-guide/

https://homeguides.sfgate.com/trees-balconies-63599.html

https://www.theglobeandmail.com/life/home-and-garden/spring-cleaning/tips-for-high-rise-gardening/article4266735/

For professional assistance, check with Landscape Ontario which is the professional association for the horticultural trades.

Best of luck with your balcony garden!