I think the clematis will outgrow and smother either of the roses. And, aesthetically speaking, I don't thin MjC clematis will look good with Don Juan...I think the reds will clash...I tried the clematis Abundance with Chevy Chase, and I hate the combination. One of the few combinations I don't like....both are "reds".

Robert

Robert...why do you think the clematis will smother those climbing roses?..I think that Clematis "Mme Julia Correvon" would look stunning with your white climbing rose "Sombreuil"... and Robert is right "Don Juan" is red and your should probably plant a white or dark purple to compliment the red...and truly show up..I have clematis "Ernest Markham" try and be sassy by growing over and grabbing ahold of one of the canes on my Climbing rosa "Don Juan"..and those two were the ugliest thing to me..LOL...Just don't care for pink and red..Jeanne

Is it too late in the season to plant a clematis?

I'm thinking of moving MJC - I just planted recently anyway. I DO think a purple would probably look better with the combination of the two roses, so now I'm off for yet another clematis to add to my new collection (hubby is rolling his eyes).

Jeanne,
It was my understanding that Mme Julia Correvon was really quite aggressive...I guess I'm wrong. I put it on my biggest trellis...perhaps the information I got was wrong. Hmmmmm... maybe I need to get a different clematis for this spot. The trellis is about 15 x 15.

Robert

I decided to go with a Romantika clematis with the roses as I think this would be a better color combination. I'll add vinyl type fencing material on each side of the trellis so the roses can "fan out" and leave more room for the clematis. We'll see what happens.