heat tolerant potted plants for balcony

(Question)

I am wondering what type of (potted) plants are suitable for a south facing balcony in southwestern ontario near Lake Ontario? it does become very hot on the balcony mid-day and in the afternoon.
Thank you!

(Answer)

Thank you for contacting the Toronto Master Gardeners.

Balcony gardening has become a very “hot” tlots of information on our website topic in the last few years. We have lots of information on our website concerning balcony gardening. On the torontomastergardeners.ca website simply type “balcony gardening” in the search bar located to the right of the page.

Before you begin deciding on the plants there are a number of things you need to take into consideration. Are you interested in planting annuals or perennials? The following information is a summary from some of our archived posts:

“Wind consideration: Is the balcony sheltered or exposed to prevailing winds or wind-tunnel effect? Wind is perhaps the biggest challenge to balcony gardening–wind will dry out the soil in containers easily–consistent and effective watering is required. And the higher your balcony is from the ground, the windier the conditions. Creating a windbreak using a trellis or screen or native shrubs like juniper or viburnum will help shield plants from the wind.

Before deciding on what type of planters to use, be sure to check your building regulations – check if planters or trellises can be attached to walls or railings and consider weight restrictions if you’ll be using large planters; wet soil is heavy. Consider plastic or fibreglass containers rather than heavier clay, concrete or metal. And be sure all containers have drainage hole. Consider how you’ll do the watering and if the neighbors’ balcony is directly below, ensure drainage goes the right direction in the event of overflow.

Size of containers: If you plan to grow perennials, you will need large enough 4-season insulated containers that will withstand the changes in temperature throughout the seasons. Note: You should check with your building management for regulations in use of balcony space–safety concerns and weight considerations. For perennials, containers will need to be at least 40 cm. (16”) in height and width. You may need to consider lightweight alternatives for containers and soil.

‘Right plant, right place’ is even more important on a balcony than on the ground–one must consider the recommended growing zone for perennials; select plants that are at least 2 zones hardier than the normal zone [i.e. for Toronto (zone 6a), plants should be hardy to zone 4.

A south facing balcony is a good spot for sun-loving annuals such as dianthus, geraniums, petunias, million bells, osteospermum (a fairly drought-tolerant, daisy-like flower) annual phlox, verbena  and marigolds that require at least six hours of sunshine daily. You might even consider such sun-loving tropicals as jasmine, frangipani, gardenia or oleander. Using plants of varying heights, including  flowering vines and potted shrubs and trees is most effective.

 Small shrubs might include roses, hibiscus, azalea, buddleia (butterfly bush) and boxwood. If you do include shrubs be sure you can get them through the elevator doors and whether they will survive the winter or need to be brought in?”

The Toronto Master gardeners have a number of Gardening Guides which you might find useful:

Drought Tolerant Annuals, Long Blooming Perennials, and lastly,Toronto Master Gardeners has a Garden Guide on Pollinator Gardening with a good section on attracting pollinators to your balcony.

For more information about balcony gardening with perennials, please see:

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

Petra Donnelly-petra.email@rogers.com