I am just wondering if I can grow this tree in St. Catharines and if it is possible from seed? I can buy the seeds on Etsy. http://landsthetica.tumblr.com/post/80926961203/plant-a-day-mexican-flowering-dogwood
Hello and thank you for contacting the Toronto Master Gardeners .
When researching your question I must say I was very impressed with the pictures of the fantastic blooms of this little know species of Cornus or Dogwood. I can certainly see why you would be tempted to try to grow one. The Cornus family includes a large range of shrubs and trees that can grow in zones 2 to 9. Your Mexican Dogwood is a subspecies of Cornus florida or Flowering Dogwood. They can grow in (Canadian hardiness ) zones 5 to 9. St Catherines is in Zone 6b. So technically you should be safe in growing this tree, but you should carefully inspect you garden as “micro-climates” can exist depending on the conditions in your garden. for example, if your garden is exposed to North winds, your Zone may be more similar to a Zone 5 than a 6! Dogwoods grow well in light to partial shade, in soil of average to high fertility, is high in organic material and that is well drained.
These flowering Dogwoods are also very susceptible to blight, canker and powdery mildew. While I applaud your enthusiasm in trying this tree, if you wish to avoid disappointment down the road you may want to try a slightly hardier species such as Kousa Dogwood as it is more resistant to many of the maladies that affect Cornus florida.