Cornus florida is at the extreme northern edge of its range in Ontario. Which means that, in most years, a late spring frost will kill the flower buds.

I have a eight year old dogwood, started at 5ft tall and now close to 10ft; have seen exactly one bloom in those years.

They set their buds in the fall, though, and I've only seen it do so once. (The next spring the buds flowered). I may have to give it away if its not likely to bloom well - I don't have that much garden space.

If you want a good flowering dogwood that's about the same shape and size as the Florida version, get a Cornus alternifolia. It's native to here (you in London, me in Woodstock) and we have one growing naturally and nicely in deep shade in our woods. Even with the deep shade it gets lots of pannicles of flowers so in as much sun as you have, it would likely produce a grand amount of flowers. It 'is' technically an understory shrub so you may wish to position for a bit less length of sun than your current one but I can highly recommend this native shrub from experience and it is now showing up regularly in regular garden nurseries as part of their stock. I would suggest calling ahead to see if specific nurseries have it so you don't waste gasoline but in London I don't think you'll have any trouble finding one. I'm pretty sure the Nursery up in Hyde Park will have one but I don't know the name of the Nursery...??? Hyde Park Nursery??? lol.

Barb/knottyceltic
southern Ontario, CANADA

I'm thinking that if it doesn't bloom for me next spring, I'm going to find another home for it and then replace it with a Cornus kousa "Wolf Eyes" youngster which I bought last year, not really thinking of the fact that I don't have much room for it... I have seen nice blooming Cornus florida in London before but I guess they were in more sheltered microclimates or something. It's a shame to have to let it go when it's finally developing its form and is a decent height, but if I let it go any longer I probably won't be able to move it! Anyone interested in a trade?

Barb is the tree from a genome of this area - Floridas is a very finicky tree - needs lite sandy loams.

Barb,
I have some small potted Cornus kousa that I would trade for your Cornus florida. My C. kousa's are seed grown and have yet to flower but they are nice 3 - 4' trees ..
I don't know how well your tree will transplant but I would be willing to give it a try ..
a.

I also recommend the alternifolia. They are also called Pagoda dogwood, as the branches are very regularly spaced, and it has a pagoda shape. White flowers.
We had a Kousa, but the rabbits ate it all!

Hey barb,
I am also in Canada in your zone and have a flowering dogwood 'Rainbow' tree (Cornus florida) on my backyard. Same problem: never seen it blooming, though every fall it sets loads of green buds, but in spring I always find these buds dead as doornails and completely dry.
I am growing it for 5 years already. My 'Rainbow' is a variegated variety, it is so beautiful even without blooms that I do not care much about flowers. Of course, blooms would be an added bonus, so I will wait........

What is the REAL maximum size of Cornus alternifolia (in partial shade; partial sun)? Some sites say 15' some say 35' wide. In nature, left to spread, would it grow to 30' wide and 30' tall?