Can I plant a store bought indoor azalea outside in Toronto?
The colourful Azaleas offered for sale as houseplants may look a lot like their outdoor cousins, but sadly they are not hardy and will not survive our winter if planted outdoors.
The scientific name of Azalea is Rhododendron, which encompasses over 800 species ranging from evergreen to deciduous, from subtropical to very winter hardy. The species of Rhododendron that are sold in supermarkets and flower shops are Rhododendron simsii (Indian Azalea) and R. obtusum f. japonicum (Japanese Azalea), which are hardy only to zone 10.
Do not be discouraged, however, for it is not difficult to keep your beautiful Azalea as a houseplant and induce it to bloom again. You can bring the plant outdoors after all danger of frost is past, and place it in a semi-shady spot. Keep it very well-watered, taking care to never let the root ball dry out (this is important because Azalea is usually potted in peat moss, which, once it dries out, is very difficult to moisten again). Also make sure that the roots are not soggy wet; otherwise the plant will drown. After it has finished flowering, feed with a lime-free flower fertilizer or rhododendron food in a low concentration, every 2 weeks until August. In the fall, bring it back indoors to a bright cool spot with no direct sunlight. Cut back on the watering a bit to induce bud formation. Keep it in at temperature around 5ºC to ripen the buds. Once the buds are swelling, move it to a warmer location of around 18ºC. Then watch the magic happen.
If you decide to keep your Azalea for longer than a year, then remember to deadhead regularly and repot every 2 years. You can prune it in early summer to promote bushier growth. Good luck!