I live in a Townhouse in Mississauga and wanted to create a hedge wall that will block myself and my neighbours. I have been researching the Leylandii Hedge but it may not be hardy enough for our environment even though Port Credit rarely goes below -10 in the winter. There is large Maple Tree growing above the area that I want the hedge with limited sun (some but blocked by tree). I would like it to grow fast and be 6ft or taller, I can trim regularly, water and provide good soil. What would you recommend?
Cuprocyparis x leylandii prefers a moist but well drained location with full sun and is hardy in zone 6 – 10 (ref. Missouri Botanical Garden). The presence of the large tree means it will be in partial shade not full sun. In addition, you may be taking a chance with using leylandii cypress for your hedge even though where you are located has mostly mild winters. It is the odd colder winter that could kill the trees. There are some varieties that are hardy to zone 5 but you may be hard pressed to locate them locally. There are other options that you could consider. Below are several links for more information about leylandii cypress used for hedges and how to locate other hedging material. Note in particular our gardening guide for evergreen hedging where you may find some alternative options to using leylandii cypress.
The third link is a response to a question about hedging and the section about planting Hicks Yews (Taxus x media ‘Hicksii’) may be what you are looking for. Yews, while not fast growing , are readily available in Ontario and tolerate partial shade as well as some drought. They can be easily maintained with pruning.
https://www.torontomastergardeners.ca/askagardener/leylandii-or-laurel-hedge/
https://www.torontomastergardeners.ca/askagardener/hicks-yew-hedges-and-baltic-ivy/