Funny Sherry, I always think of Santa Cruz as being warmer than AG. Well, I'm way inland. Think micro-mini Sierra Nevada. I'm just behind Lopez Lake. My neighbor, (1/2 mile away as the crow flies) says that the change in temperature when leaving their house to arriving at mine is 20 degrees! Micro-climates, Argh.
'just lucky I guess.

New Dawn is thriving in my backyard(which, being lakeside,tends to lean towards zone 6b). Her long, highly thorny arms are heading up a cottonwood so the BIG show of blooms come late spring,scattered blooms thru out summer. NEVER seen any Blackspot on her..this hardy rose had a foot or more of water at her base for 2+weeks, flood of June 2015. She thrived!

Growing roses up through mature trees seems like a challenge. Besides the shade there is the problem of root competition. Not sure all the following roses would survive either one. One might consider growing it to something more than head-high in a 24 inch pot and in a location that gets extra light. (Or move it twice a day on a dolly to catch the light. Just an idea...)

Paul's Himalayan Musk is sold as a rose to scramble through trees, but I lost mine in the first year. Mme Alfred Carriere is the most vigorous rose in my garden, and could easily cover a pergola or smallish tree. I've seen Gruss an Zabern trained to reach 20 ft in two opposite directions. And I know that it will grow in deep shade. It's not a very sophisticted blossom, but it can be quite vigorous and very generous in bloom.

I've grown New Dawn in zone 8a in TX, at the base of a downspout on south-facing wall and it easily reached 15 ft in one season. Sport Awakening has reached half that here in zone 7b in twice the time. I've seen photos of Coral Dawn scrambling across reddish roof tiles; and its a good look. Half-sister Blossomtime seems rather less vigorous in my garden being waist high at four years of age. While we're talking about wichuriana climbers, I wonder if something like Alberic Barbiere or Francoise Juranville might work?

Alexander Mc Kenzie can grow huge, and its purplish flowers have an air of distinction. John Cabot or several other of the Canadian Explorer series might merit a look. I've heard that Dortmund can grow to great heights. Lots of vigor, lots of color; maybe not so much refinement.

I'm very pleased with Malvern Hills, but it took a full five years to produce its first nine-foot long cane. I imagine its good for half again that height in ideal conditions.

Peggy Martin will be happy to climb your tree. If you can plant her on the south side leaning in the right direction, and give her a little guidance, I am pretty sure she will take it from there.

LlamaLlori said:Funny Sherry, I always think of Santa Cruz as being warmer than AG. Well, I'm way inland. Think micro-mini Sierra Nevada. I'm just behind Lopez Lake. My neighbor, (1/2 mile away as the crow flies) says that the change in temperature when leaving their house to arriving at mine is 20 degrees! Micro-climates, Argh.
'just lucky I guess.

Ya' know....many people think of California as one big tropical state. They have NO idea of all the microclimates that we have. and sometimes a zone 8 can have snow in Nov, Dec, Jan Feb, Mar and April, though I do not recall having snow in May. Yes, snow off and on and the rain this year has prevented me from doing much gardening activity, so the weeds in the gardens are overwhelming. I don't use any weed-killer, except vinegar for places that have no plants in there, like the gravel driveway. So I do garden by hand. At 75 I am not as fast as I used to be, so it will take me from now until the snow or rain falls in autumn.

Before moving to El Dorado county in 1987, I lived in Topanga, so I know about canyon frosts and cold in spring.

I have ordered climbing Iceberg. Do you have any idea what will be my worst challenge? I also have a white Lady Banks rose, which does grow very well up here, though none in my neighborhood, just lower down in the foothills like Diamond Springs or Placerville. (Right now it is small, as I bought it as a one gallon plant.) I think that once Lady Banks grows up, my biggest challenge will be keeping it cut back, so it doesn't take over.