Wisteria growing in a pot

(Question)

My wisteria is 6 years old
It has been in a large pot on ground in a backyard in Belleville
Every June it come out of dormancy and is beautiful.
I now leave downtown Toronto on the 32nd floor.
What do I need to do for the wisteria to survive ?

(Answer)

Growing wisteria on a 32nd-floor balcony in Toronto can be a bit challenging, but it’s possible with proper care and attention.

Your first considerations are variety, container choice, sun and soil. You don’t mention the variety of wisteria you have, but for container gardening you want to choose a suitable variety. Chinese wisteria (Wisteria sinensis) and Japanese wisteria (Wisteria floribunda) are common choices but these can grow quite high so you might want to opt for a variety that isn’t so large such as the American wisteria (Wisteria frutescens).. Ideally you should choose a dwarf or smaller variety that is more manageable for a balcony. Use a large, sturdy container with excellent drainage. A container at least 15-20 gallons in size (57-75 litres) is ideal. Ensure it has drainage holes at the bottom to prevent waterlogged soil.  It’s generally recommended to use a container that is 3-4 times the size of the root ball, and to repot the vine as it outgrows the container. Use a well-draining potting mix that retains moisture but doesn’t become soggy. Adding perlite or sand to your mix can help improve drainage. Wisteria thrives in full sun, so place your container in a location on your balcony where it receives at least 6-8 hours of direct sunlight each day.

You’ll also need to consider support, wind, pruning, watering and fertilizing. Wisteria is a vine that needs support for its growth. Provide a trellis, arbor, or some form of support structure on your balcony for the plant to climb. Make sure it’s securely anchored to prevent it from falling in strong winds. On the 32nd floor there will be wind considerations, depending which direction you face. You may need to provide a wind screen for your wisteria. Regular pruning is essential to keep your wisteria in check and promote flowering. Prune in late winter or early spring to remove excess growth and shape the plant. You may need to prune more frequently to maintain size constraints in a container. In addition to regular pruning, you may need to prune your wisteria to keep it within the confines of your balcony. Container plants typically require more frequent watering than those in the ground. Keep the soil consistently moist but not waterlogged. Water when the top inch of soil feels dry to the touch. Be mindful not to overwater, as this can lead to root rot. Fertilize your wisteria with a balanced, slow-release fertilizer in the spring. Avoid over-fertilizing, as it can lead to excessive foliage growth at the expense of flowers.

Wisteria may be susceptible to cold temperatures on a high-rise balcony. Consider wrapping the container in bubble wrap or providing some insulation to protect the roots during harsh winter conditions. Make sure that your container is not placed directly on the ground but is placed on small blocks. This is because once the temperature drops and the ground freezes under the container, water cannot escape the bottom of the pot. The container will thaw before the ground does and if you get a few rainy days, the water will stand in the pot, either rotting the roots or turning into an ice cube when the weather chills again.

With proper care, your wisteria can be a beautiful addition to your 32nd-floor balcony garden in Toronto.

October 8, 2023