We have a SAC on a chain link fence in proximity to two once-a-year blooming roses, Russelliana (Russell's Cottage Rose) and what's known around here as Seven Sisters (but I think is really Excelsia). Each plant is about eight feet apart and in partial shade -- really only 4-5 hr/day of sun. Right now the SAC is in full bloom and the location looked great in June, too, when the rambling roses bloomed. All three plants are happily duking it out. There was a Constance Spry involved in the fray on the fence, but one of the others choked it out this year. It's a part of our garden that's pretty neglected and these three are just perfect for that location. We'd probably lose small children to these plants if they got more sunlight and proper care.

Hey fellow gardenstater! I live in OH now but grew up in NJ near Asbury Park! lol To help with you question... I am trying to do the same thing here with a new clem Henryi, and several others and my John Cabot rose which is coming in a couple of weeks. I am also constrained by space because they are against a trellis. Since 'Haku Ookan' is a group 2 clem you might want to consider the two side by side? Think in terms of not only water and nutrient requirements, but which way will be easier to prune both? Clems don't really need to have "their roots shaded" as what they really need is Moisture! The roots shaded by mulch or low growing plants (or the rose for that matter) is only there to keep the clem and rose moist. If you can't plant them side by side I would tend to think in terms of planting the clem in front of the rose. Of course, it is all up to you. Our gardens should be done the way WE like them :) I think at least a ft is ok for the spacing if you are training it to go through the rose. But be careful digging as all roots are easily sliced through. Mine are also going to be about a ft away from eachother. Here is a pic of the general plan: (there is actually a lot more space than what is shown as the trellis is 20 ft long and 6 ft high.) But I'm not that great at drawing lol.

Thanks! I feel better now knowing that the proximity of the rose roots won't overwhelm the clematis' own root system.

Thanks for posting, Cynthia. I have hunted for that ever since I first saw it. I was particularly interested in the extensive bed prep and soil amendments she does. I'll bookmark it this time. Jim