Subject to dogwood anthracnose in some parts of the US; might do better with a D. florida x D. cornus cross. Don't know about cold temps...

Sara what is D.? Is dogwood no longer in the genus Cornus?

splaker, where I grew up in Cleveland, Ohio, the soil was only very slightly acidic and had a lot of clay in the soil; in places we could form it into pots. Dogwood did fine there and is a common choice for yards as well as Cornus florida growing wild.

My current location is on the edge of 4b, and we do get below -20F occasionally, but not below -25F. I haven’t had damage on Cornus florida, but Cornus kousa has been damaged, with a lot of branch dieback when it got below -20F. I think that this is a situation where provenance is important since trees whose genetic material comes from the northern end of the range is more likely to have been selected for survival in colder temperatures than ones from more southern genetic sources. Siting may also play a role. In our coldest winter that damaged the Kousa, the one in an exposed site with no shelter had a fair amount of damage while the one sited at the top of a slope and surrounded by other trees didn’t have damage. Both are open seeded and I don’t have a location for where they came from.

Seed grown tree from London, ON provenance is completely hardy just north of King City, ON....hope that helps. Anthracnose hasn't been an issue for this tree.

There are a number of specialty nurseries in SW Ontario now offering Cornus florida grown from local seed...you'll have better luck with that than named varieties of C. florida or even C. florida (straight species) from large commercial nurseries.

NHBabs(4b-5aNH)

Sara what is D.? Is dogwood no longer in the genus Cornus?

It's Dogwoodiia now

Splaker, C. Florida is one of the best spring and fall trees. Excellent flower show and excellent long lasting fall color.

Summer, I like their leaves, winter, they're ok but have a gentle hand pruning. Their natural forms are minda pleasing but it takes awhile for them to outgrow pruning wounds.

I love them though. Fall is with the best of the maples and nyssa sylvatica in my opinion.

My fault! Should have typed C instead typed D.

C. alternifolia is common here too. It's a wonderful tree but other than it being in the genus Cornus, it isn't much like C. florida (for landscape purposes).

I planted a C. alternifolia last fall! In the backyard in a moist spot that gets sun but some shade too... looking forward to it as it comes highly regarded... we have lots of alternifolia in our local forests... Never seen a C. Florida in our forests.. this is the link to the tree vendor... no cultivar mentioned.. guess it's straight species:

https://www.onplants.ca/product/flowering-dogwood/

So how big should I expect it too grow (width and height)? I am seeing different ranges... Don't want it to get too big... hopefully under 20' wide and tall... can they be pruned to control size? I have the space on my property bu the site I want to plant it in is close to my front entrance and I don't want it to overwhelm the entranceway..

I'd say they are a two season tree. Not especially picky. It will be a loong time before it gets to large in your climate, if it actually lives that long.

Maybe Pagoda Dogwood (Cornus alternifolia) would be a better choice in your area? It is more cold tolerant and a little smaller.

Hawthorn (Winter King, Washington, Downy) are more "4 season" trees.

I see both C. florida and C. alternifolia as of year round interest due to the graceful branching structure. Flowers and good to great fall color add to the appeal, but I really like them regardless of time of year. At a previous house we had a pink flowered one and the leaves emerged with a lot of red tones. It was just east of a window, and the early morning sun through flowers and foliage made the tree glow.

St. Williams Nursery (wholesale) has C. florida from SW Ontario seed. They supply Springbank Garden Centre (retail). It will definitely stay within your 20' high & wide constraint.

As I do my research I am coming across a fair bit of anecdotal evidence that the Kousa dogwoods are tougher, more superior trees to the native Floridas... Comments?

How cold does your area get? How protected is the area you want to plant it in? One of my Kousas was severely damaged by -23F temperatures, so unless it stays warmer than that, I would choose a locally adapted C. florida. If you can tolerate damage which is likely to shorten tree life and influence shape, you could try the Kousa, but I think the C. florida is more likely to tolerate cold temperatures.

The main aesthetic difference is that the Kousa blooms after leaf out, while the C. florida blooms before the leaves emerge.

Interesting... this is why i love coming to this forum! You guys have so much more real world knowledge! In the four winters I've lived at my current home, the coldest temp I've experienced was -23 F. That is about as cold as it gets... but obviously colder is possible.. more typically, -18 to -20 F would be the typically "cold snap" temperatures of middle winter. And we do get those pretty frequently... I'm thinking of planting the tree at the front of my home near my entrance. This is south-facing. So, it would get some shelter from the prevailing northwesterly winds... Snow melts quickly at the front of my home compared to the north-facing backyard... it's definitely a touch warmer..

Sounds like your temperatures are very similar to mine. I will look to see if I can find a photo of the Kousa the first year after the coldest temperatures and how it has recovered in three growing seasons. It was homely enough initially that had it been in front of the house I would have removed it. As it is behind the house, it isn’t visible to most folks so I left it to recover.

Edited to add:

Here it is leafing out after -23F and in "full bloom" (see the tuft of flowers that were below the snow line just to the left of the trunk). It wasn't helped by an early heavy wet snow fall the previous autumn while it was still fully leafed out. It didn't break any branches, but did a fair amount of damage, causing the overall look to be misshapen since it was bent down to about 4' from something like 12' at the time and didn't fully recover from that either.

Here it is in September having thrown out a whole lot of new growth where branches weren't outright killed. I did a lot of pruning that spring and both springs since, and it is finally starting to look like a reasonable tree again. I will most likely need to do a bit of pruning this spring as well, but not nearly as much. If you want, I will add another photo after it has leafed out this spring.

the florida is a northern seed according the supplier...but said it won't survive as it needs Z6. Thought Z5 is okay..