Thank you for contacting Toronto Master Gardeners.
The Rose of Sharon, Hibiscus syriacus, is a beautiful shrub which blooms later than most shrubs in the garden. It does best with full sun or partial shade and well drained soil. You will want to ensure you pick a variety that matches your zone. Ottawa can have harsh cold winters so a shrub that thrives in Toronto may not like the colder weather in your Neighbourhood.
For ordering your shrub you are best to visit your local nursery to see whentheir shipments of the shrubs arrive. They will also have an idea which varieties will thrive in your area. Getting there early will give you an opportunity to chose the strongest best shaped specimens. Do check the information with the plant on the mature shrub size as many do grow larger than 4-6 feet. Flowers develop on new wood so timing of pruning to maintain the 4-6 foot size will need to be planned for post blooming so you do not lose any buds.
I am including links below with further information on the Rose of Sharon as well as a resource from Master Gardeners with guidelines for planting the Rose of Sharon.