Kevin, haven't answered your question until now since I was not sure if there had been any hybridization done with drummondii. Still don't know the answer to the question but it sounds like a plan. Have you ever considered giving it a go? They crossed flammula, a rather nondescript white flowering clematis, with the species viticella and got Triternata Rubromarginata out of the cross. Just realize that the results of the crossing of drummondii with any other clematis would be unknown since the crossing of the two sets of chromosomes would give you a mixture whose outcome you couldn't guess.

Well, I feel kind of like a kibbitzer at a card game, because my aspirations as a plant breeder have always foundered on my lack of land. Unfortunately, its not a dollar an acre like it was in Luther Burbank's day! I was curious if anyone had done it, and thought it worthwhile to throw the idea out there for someone who could. There is a slight paucity of plants that will take our extreme heat, and it's frustrating to see all these beautiful plants in catalogs, knowing that you can't grow them here!

Frustrated, but not giving up!
Kevin : ]

Kevin, to be quite honest I have never seen C. drummondii offered for sale by any of the usual clematis vendors. It might be something that is offered by local nurseries where it naturally grows. Even COTW does not have a picture of it and has little information on it. Its apparent unavailability may hinder anyone's opportunity to propogate/hybridize with it. Top that off with the fact that I have yet to see any documented general rules as to which types of clematis will cross with other types and that would further hinder one's ability to do crosses with it. The English and Europeans seem to be the ones that have traditionally been interested in the US native clematis for plants to grow and to use to hybridize new clematis varieties from. Perhaps someone here in the US who has access to this clematis will take up this line of potential hybridization.

Of course as soon as I hit the submit button I thought of something I wanted to add. I am unsure which clematis you have attempted to grow in your zone 9 garden. Have you ever attempted growing clematis texensis which is native to Texas or campaniflora or viticella or any of the viticella hybrids? Some of these might be better suited to your growing conditions. My limited experience with the large flowering hybrids has lead me to the conclusion that they generally don't do well in extremely hot climates. Something to think about.

Check with the Ladybird Johnson Wildflower Center, www.wildflower.org, for info and images. Plants or seeds may be available at the Phoenix Desert Botanical Garden, www.dbg.org, or they may know someone else who has them for sale.

I have looked for C. texensis, but haven't found a good source. Researching it, it also seemed to be a high elevation species, which will cut into its heat tolerance. I have grown C. viticella, and it didn't seem to be any more heat tolerant than the large-flowered hybrids. I still haven't tried C. campaniflora, so that's my next topic of research.

Thanks for all the info nckvilledudes!
Kevin : )

No problem Kevin. I grow texensis here in NC and it does just fine and I am not at any high elevation. Dan Long at Brushwood sells it but I see that it is listed as sold out. You can always contact him and see when it might be available. He also has campaniflora. Ellen Hornig at Seneca Hill Perennials sells texensis and it is in stock. Joy Creek sells a version called the Tarpley River form that was collected from a ranch in San Antonio, Tx. I got one last year and it did quite well in my garden in a large pot.

Just realize that if you are trying to grow clematis in a hot and humid climate that it would do you well to plant it so that it gets morning sun and afternoon shade. Amending the soil with organic matter and using a good mulch that will break down and add more tilth to the soil wouldn't hurt either. Watering of course is a must. I might be preaching to the choir here if you have already tried doing all the above but just wanted to make sure!

Yep, those are considered just good gardening practices here, especially with species from cooler climates. Just remember that NC, even in the lowlands, is a far sight cooler than we are here in Phoenix, AZ! We aren't very humid by your lights here, even in the monsoon season, but 115°+ days and 95°+ nights do terrible things to some plants even when the humidity is only about 50%. So you see why I want to find out as much as I can before I commit much of my money or precious space to anything. I keep thinking that if C. texensis did that well here, it would already be offered in some of the local nurseries, though they're a stick-in-the-mud lot here.

Thanks again, nckvilledudes!
Kevin : )

Oh for sure about the cooler temps here Kevin. Visited Phoenix one year in October and it was still above 100 degrees. Even then though I didn't sweat 1/10 as much as I would have had I been at home and it had been that hot here! LOL

No problem Kevin, glad to be of help. Just realize that there are very few nurseries that offer the native US clematis. It is just a shame about that since there are some very gorgeous clematis in that bunch. You do good to find much more than the LFH here at most local nurseries. Trying to find any of the viticellas here is pretty much hit or miss!

C. drummondii certainly does have heat tolerance (given its locale in AZ, TX, etc.) but it has adapted to it with a pretty boring flower - almost all stamens. I know of no crosses, though seeds are often available.

For similar heat tolerance, I would go try C. flammula that Miguel mentions - I have plants from seed collected from Sicily, Corsica and southern Italy, all of which rival AZ for heat. Species viticellas are also found in some of these areas - have you tried the species (not its hybrids)? C. campaniflora is from even further south, Spain and Portugal, so that certainly is worth a try.

C. texensis, C. reticulata and C. pitcheri would be some other ones often found in southern U.S. climates and are easily enough found at places like Joy Creek, Brushwood, Seneca Hills, etc. Reticulata and texensis would be the most heat-worthy, I think.