Yoshino is a spreading habit, the other more upright

Yoshino has white/pale pinkish flowers while Kanzan has double (frilly) pink pom-poms.

I think Yoshino is the more attractive tree of the two both for the flowers and the form.

Thanks for the replies -- really helpful. Today I went to get the last Yoshino at my local nursery. Turns out it was aphid-ridden and sickly. They tried to sell it to me anyway.

Well, they do have several nice autumn flowering ones (Prunus subhirtella Autumnalis). I'd greatly appreciate ANY advice on this one, too. I have to purchase this week (long story, store credit issue). I notice that the 'autumn flowering' has smaller leaves and looks more delicate. Other than that, well, I'm a tree novice...! Thanks for any opinions.... --Dwight

Dwight, I am not personally familiar with growing P. subhirtella Autumnalis but the ones I have seen have been attractive trees. I don't know when you would get flowers - here, there are light, scattered blooms in the fall, and then a goodly show in the early spring. I think, if the trees are healthy looking, that they would be a good choice. You might give a call to the arboretum, and ask them about suitability, and about bloom times, as I am sure they have specimens growing there.

No I'd skip the autumnalis those are supposed to be even more prone to disease and short lived. Get something else.

I have no experience with it in your climate, but I'd avoid the 'Autumnalis' as well. Here they are a dog - while they may offer some fall flower color, they are most often disease-riddled and sparse of foliage. Most local nurseries no longer offer them for sale.

If you HAVE to get a tree from the nursery within the next week - why not try for one of the native flowering trees? Serviceberry, redbud, fringe tree, dogwood(s) might all be available, as well as others. If not one of them, maybe a pussy willow, or else flowering crabapple - just be sure to get a disease resistant one. A nice small maple might be possible - Acer griseum, A. ginnala, A. davidii, one of the larger Japanese maples - or else American holly, a selected deciduous magnolia, sourwood, Stewartia, styrax, Japanese tree lilac, blackhaw or nannyberry could be possible - all stay small, all have flowers or foliage, some have berries or winter interest. Only the holly is evergreen, in that list, so maybe looking at more evergreens might be possible too.

Good luck. You might end up paying a little more, to get s nice tree, and to clear the store credit.

I grew up in the Washington D.C. area and always loved the Cherry Blossom Festival trees.
I thought all Yoshino cherry trees had the soft pale pink blooms I remembered from childhood, so I planted one.
To my dismay, I found out after my Yoshino bloomed WHITE that what I really wanted was the 'Akebono' cultivar of Yoshino cherry tree. The Yoshino has white blooms, whereas the 'Akebono' cultivar of Yoshino has the pale pink blossoms. I mail-ordered my Akebono from Greenwood Nursery (www.Greenwoodnursery.com) bare-root and it's growing great!
I also like the 'Kanzan'. It has extravagant double blooms in a deeper pink and the tree is vase-shaped. I've seen young ones pruned like a standard with the top rounded and it looks really nice.
These trees grow EXTREMELY fast - my white yoshino is 12 x 15 feet and is only 4 years old.
The downside is they are relatively short-lived (I've read, no personal experience) due to the fact they can succumb to diseases & pests fairly easily. I don't care - they look absolutely glorious while they last - to me they're well worth it for 10+ years of pure beauty.

If you cut and paste this link it shows Yoshino cherry trees in full bloom: http://www.pbase.com/bryan_murahashi/040503_nationalcherryfestival&page=1

PS - my Kanzan does not have muddy pink flowers at all. They are a rich, beautiful pink!

If you cut & paste this link you can see good pics of the Kanzan (aka Kwanzan) tree:
http://www.webshots.com/explore/Kwanzan+Cherry

Enjoyed reading all of these follow-ups. And Sue thanks for the photo link. I did end up getting the autumn flowering cherry. I almost threw out the entire idea of a cherry when I saw a 'Butterflies' Magnolia at the nursery (wow). But, I got the cherry so I'll deal with whatever transpires.

Please check my article Kwanzan vs Yoshino Cherry Tree: What to choose? There I describe all differences between these two varieties.