Cateyanne, I would do exactly that,cut the sweet autumn to the ground. She is a tough one and severe pruning will not hurt her. Just out of curiosity, appox. are you in northern Ohio. I am in the Warren,Cortland area.

Thanks jaco,
I am right on the Lake, west of Cleveland.

The land of Nurseries I would be completely broke if I lived any closer to them

Considering the growth habit of each....one grows to 10 - 12 feet...the other as high as --the stars...I would say they are not good companions for the same trellis.
One is much heavier than the other.

While both are Class C's, they have distinct different growing patterns. While one has given up the ghost in early fall, the other is just coming into its heavy period.

The Jackmanii is cut back in early spring as does the other one, but considering the mass of bloom on the later bloomer, it could envelop the Jackmanii and any blooms might be swallowed up by the mass of foliage.

I find you are indeed correct goren. The sweet autumn completely powers out the Jackmanii. I have cut them both down and I will see what happens. The Jacmanii doesn't appear to be doing anything yet, it could still be early, but I am a little worried as the autumn is already leafing out. I hope it didn't strangle to death. I may move it if it lives!

Any ideas on what varieties would work well together? Either a partner for the late blooming Sweet Autumn or completely different pairings? I've got LOTS of trellis to cover!!

These are both varieties that bloom best if pruned to near the ground (leave a few buds per stem) yearly. Plus, an annual prune lets you avoid the mess of dead stems in the winter. They will grow up to the same size each year after pruning. My mom had a Jackmanii in Cleveland which I pruned for her each year if I visited when it was dormant. It grew to the top of her 6' trellis and then spilled down or grew over to the railing each year from the 1 1/2 feet I pruned it to each year.

I am a bit unclear when you say you have lots of trellis to cover. If those 2 clematis were covering it previously, they most probably will this year. Or are you planning to move one of them so that they are more balanced?

One of the larger sized clematis is Betty Corning with light purple small bells. She might well be able to keep up with sweet autumn, though probably won't be quite as large. Many of the type 3 clematis other than those two will work with Jackmanii.

Sweet Autumn when mature does not usually play well with others. It usually smothers them as it is a huge grower....

I have a trellis wall that opens to an arbor then continues with another trellised wall. This structure divides the front property from the back. I need more climbers to cover it, which is my goal. I've been trying different types of clematis to see which work best.
nhbabs, sounds like you prune the clematis in the fall? to avoid dead winter stems? I thought these varieties should be pruned in the early spring? Did I get that wrong?

funny, i did just did a similar thing this spring too
the one thing i felt i needed to do was to find another clematis that could be pruned hard along with the other one to avoid a time consuming mess that i would have to navigate thru come pruning time

Sorry, Cateyanne, I thought I had previously replied to your question. I prune my clematis anytime after the temperature has gotten cold for the winter, usually some time after Thanksgiving and before March, whenever there is little enough snow cover to get to them. It's been quite a while since I lived in northern OH, and I wasn't growing clematis then, but I would think any time after Christmas would be fine.