I've really always disliked the term "Keep the roots cool" or "Roots in the shade and heads up in the sun"..what is all meant by that jargon is that Clematis like to have their roots stay moist...mulching aids in keeping them that way and so does shade...A clematis can survive in those pots as long as the caretakers are watering them often enough..and as a rule places like Lowe's and HD don't!!..Those people hit and miss and most the time I find a few potted clematis and the buggers have the soil washed off and the crown exposed!!..so, in my feeble attempt I sure hope I've explained these commonly used rhetoric...Jeanne

Good job Jeanne. You continue to see this fallacy about clematis and cool roots since it is written everywhere you look. Clematis don't need or like cool roots. They like the moisture that normally accompanies places and situations that allow the roots to stay cool (sufficient moisture or shading supplied to prevent moisture evaporation). You basically answered the question yourself Harry when you noted that clematis can survive and do quite nicely in black pots in the full sun. You see the plants in nurseries where the pots of clematis are in full sun. Moisture is the key and not the cool conditions.

I did my utter best to kill a Dr. Ruppel I picked up from Lowes last year. Left it in a one gallon pot for the entire summer. Never planted it, but watered it faithfully out of guilt that I never gave it a real spot in my garden. By the end of the season the root ball was exposed and it looked dead. This Spring it sprung with about 8 huge blooms on this little one stem wonder. Needless to say, the good Dr. holds a place of honor in my garden now. He earned it, don't you think! :)

Denise

Denise..the Dr. most definitely deserves a place of honour..LOL..he is a vigorous little bugger in my gardens..I have three of him..2 on purpose and one mislabeling incident...you'll enjoy the heck outta him...Jeanne

The local nursery does a good job caring for their stock. Venosa Violacea has over 2' of new growth and is already vining its way through the adjacent viburnum. The 4 older clematis I have entering year 3 are significantly smaller. Maybe there is some benefit to frying in a pot over the summer.

I have also noted that the Royal Velours I bought the same day is beginning to grow rapidly.

Is Venosa Violacea known to be particularly vigorous?

More likely Harry the year in the pot from the nursery gave the clematis time to concentrate on root growth and that could be why VV is taking off compared to some of the other clematis in your garden. How large was the container that VV was in when it was planted versus the size of pots that the other clematis you are referring to were in prior to them being planted?

VV in my garden has been moderately vigorous--no where as vigorous as Polish Spirit or Etoile Violette, but much more so than others. Of course my VV is planted at the base of a styrax tree and is competing with it for light, food, and water!

My VV is very vigorous..it has spread like 6 feet wide on my fence and shot of many new vines this year..it is 4 years old...I concur..living in a pot does help it to grow bigger and stronger rootsystem that will do better once in the garden..Jeanne

You guys are getting me pretty excited - I just bought VV and Dr. Ruppel late last fall. ;0)

I was at a nursery today and asked about that keep the roots cool theory and the guy told me that he plants others plants over the roots of his clematis to "shade" the roots of the clematis and it works like a charm.

Yep you can do that but it is unnecessary. Mulch them well with an organic mulch. The mulch will help keep the soil moisture level consistent and will decompose and add moisture holding capacity to the soil. Some plants will compete with the clematis for the soil moisture and nutrients and that is not a good thing!

The pots were maybe 10". Larger than I usually see clematis growing in. Although the plant was sorta fried, the roots were thick and orange. The fast growth comes from new vines which have emerged from below the soil line. The buds from the existing canes are growing into vines, but at a much slower pace.

This thread would be so much better with a picture of Venosa Violacea.

Maybe not the best picture but the first one I came across while looking for one in my Photobucket account.

{{gwi:580359}}

What a nice, rich color. I'm looking forward to this. VV is growing just outside my bedroom window.