Oh yeah, I forgot this question: I bought the 'Ville de Lyon' from Wayside Gardens, and their website says it's in pruning group 1, but everything else I see on the web says group 3. Is group 3 correct?

Yes, tree roots are a pdoblem for clematis in my opinion. They rob so much of the moisture and nutrients that clematis may well struggle.
Your Ville de Lyons are only babies still, and will take several years to reach normal size. Wayside sells 'liner plants' at a premium price. This is rather unfair to unsuspecting consumers in my opinion.
Ville de Lyon is a group 3, hard prune type, and I simply shake my head when I see well known nurseries make the mistake of incorrect pruning groups on their web site and labels. It goes to show that they don't really know or care much about the clematis they sell !
Fertilizing your clematis is really easy. Just top dress every season with manure and some rose food and perhaps bone-meal if you have it. About mid season you can repeat the rose food.
The soil alkalinity shouldn't be any problem. Clematis do well in just about any soil if they have water and nutrients. My best advice is to water, water, water and top dress with manure and rose food. Your plants will eventually take hold and shower you with flowers once they finally grow up.
Ville de Lyon has a beautiful color and it is one of my favorites with it's striking and unbelievable rosy red/pink color ! A real winner.
Suzy

Thanks, Suzy, for the informative reply. Well, at least I got them on sale from Wayside! I think they were half off. :-)

So, regarding the tree roots -- I could dig these up and transplant them, but the other spot they'd be great for is also near other tree roots (tall Swedish Aspens). I could put them in large containers or make a raised bed to try to keep them from the tree roots. Or is it your opinion that if I give them more water and nutrients, they'll start to compete better with the tree roots where they are? I'd hate to lose another season of growth if transplanting them halts their development while they catch up from the root damage. I read somewhere that clematis like to spread their roots pretty deep, so would a container be too limiting?

I don't worry much about the Koelreuteria tree roots, but right around that birch, its roots must be incredibly invasive, because even weeds don't grow very well under it!

Hi there.
I agree with Suzy, they are still babies. If you were able to dig a planting hole about 12-18 inches deep, then those clems should do just fine. I have the same one here in Phoenix and it was blooming in full shade this past summer in a nursery pot! It is planted in full sun now and so far is doing well. It is young and not so glorious yet, but I am a proud dad so I posted a pic in the Gallery. I like it because is shows the wonderful coloring, plus all three stages - buds, blooms and seed heads. Take a look if you are interested.
David

Ooops!

I was talking about Madame Julia Correvon, sorry. But I think the same info applies. I have Ville De Lyon, too, but it has not started growing yet.
So sorry.
David

Stevation, I would be inclined to leave your clematis where they are for a few years to see if they can overcome the competition from the tree roots, but I would give them lots of extra water and a good top-dressing of manure and fertilizer for added insurance.

David, Julia Correvon is a gorgeous group 3 that I love for it's vigor and strong Vitticella genes. I have 2 plants. The one in full sun is 'going gangbusters', but the one in partial shade is not, so I think you planted yours in the right situation. Through the years I've noticed that all the Vitticella types seem to do much better when in full sun, as opposed to partial shade.
Suzy