Kitova, definitely not in zone 6 or colder but the only sage advice I can offer is that the only way that you will know for certain is to try it for yourself. All people in zone 6 and colder do not have the same growing conditions. Zone 6 just means that people in that zone have the same average maximum and minimum temperatures. It does not take into account the temperature swings, individual microclimates that people in that zone experience, windchills, the amount of wooded or shaded area around the plants that could delay their developement in the spring or allow them to grow later in the season, the individual vigor of the type IIs you might grow in that zone (some are real dogs regardless of how you treat them and where you grow them), the relative humidity in the area, etc.

I have posted this before but I am posting this again because this is important information that Ellen Horning of Seneca Hill has posted on her website and that anyone would benefit from reading:

Plant hardiness
We can repeat this rant until we're blue in the face: hardiness zones do not tell you most of what you need to know to grow many plants. For example, Syracuse, New York and Omaha, Nebraska, are both in zone 5. Do you really think their growing conditions are similar? Of course not. The totality of the growing climate, not just the winter low temperature, affects the plant's performance. Snow cover, soil type, presence of pathogens and predators, patterns of temperature change, patterns and amounts of rainfall, drainage, and other things all matter. Is there any simple way to summarize growing conditions? No. A good gardener experiments. A good gardener kills a lot of plants. A good gardener is not literal-minded about hardiness zones, either way.

To complicate matters, when you attempt to grow plants from ecosystems very different from your own (some of our South Africans, for example), it may be impossible to predict whether they will do well for you, because too little is known about their cultural requirements. Oswego does not much resemble the Drakensberg, but a lot of Drakensberg natives seem to like Oswego. Why? We aren't sure. Maybe we just have a magical mix of conditions. Doubtless you too have a magical mix of conditions, but perhaps it suits a different set of plants. You must be willing to experiment, because we simply cannot tell you whether any given plant will do well for you.

The bottom line here is that we include hardiness zones largely to pander to popular prejudice and give you a small degree of guidance. The fact that your zone number is equal to or lower than the one given for a particular plant must not be construed as an assurance that this plant will grow for you.

In addition, back when the post that you pulled up was going on, I posted asking for people to comment on how their type IIs did when pruned as a type III. I have no way to post it in its original form since it is in an Excel spreadsheet but here is my best attempt to reproduce it. I am only going to list entries I have for those people who posted and were in zone 6 or lower. The information lists the cultivar of type II clematis grown, when pruned back, did the plant bloom as normal with the same vigor as if not pruning back, the growing zone, the name of the poster, and any additional comments the poster might have made:

Gillian Blades Late March/ Early April Bloom?-No Z6/7 Massachusetts Suzy

Guernsey Cream Late March/ Early April Bloom?-No Z6/7 Massachusetts Suzy

H. F. Young Mid April Bloom?-Yes Z6/7 New York Bellport Bloomed that July after April pruning to 2"

Mrs. N. Thompson Late March/Early April Bloom?-No 6/7 Massachusetts Suzy

Nelly Moser March Bloom?-Yes Z5 Mid. Michigan Sunnyday2day

Ramona Mid April Bloom?-Yes Z6/7 New York Bellport Bloomed that July after April pruning to 2"

Silver Moon Early Spring Bloom?-Yes Z4/5 ME Cindy T
Cut back to 18 inches, 2yr. old plant

Wada's Primrose Late March/ Early April Bloom?-No Z6/7 Massachusetts Suzy

Will Goodwin Mid April Bloom?-Yes 6Z/7 New York Bellport Bloomed that July after April pruning to 2"

What you can see is that Suzy did not have luck pruning her type IIs back but others, some in colder zones did have luck with doing so. So information gathered from people in zones 6 and colder may not tell you whether a specific cultivar of type II clematis will do well with hard spring pruning or not. Your experience will tell you that better than anything else.

Hey Miguel, thanks for that info from your database. Also I knew you would respond with the zone disclaimer! I was even thinking of finding a post with Ellen's quote to put in my message but then it was running too long and i ran out of time.. anyway, i agree with what you're saying: that you'd expect or at least hope that everyone approaches the information on this forum in a nuanced way, nothing is set in stone, and practical information is always useful if not downright enjoyable when read in the right context.

honestly I couldn't find an easy way to say: what are people's experiences in the colder climates of the northeast .. and when i think about it more clearly, what prompted me to post this thread was really that i started pruning my group 2's right after their spring flush because they look so ugly and i was thinking about having a discussion about doing a post-bloom 1/2 haircut in june versus a pre-bloom hard prune in early april.

so if anyone has any experiences to share, i'd love to hear it. thank you!

Well this is the 2nd time I have responded Kitova, hopefully this time it will go through--been having some issues with this website not posting things that I write and when I go back to the thread the webpage looking really screwy.

Glad you took the info in the manner it was provided--sharing of info from several people form the past. Also, with the disclaimer that your own experiences in your zone are the best advice you can follow. LOL Will watch this thread with interest and add any info to my spreadsheet. As I said in another post, I am a scientist by training, love the nuts and bolts of data, and since I am currently working in the quality assurance area, I like collecting and analyzing data. Let the data roll!! LOL

Hi Miguel, well i have to say, being a scientist by training myself, i was tickled pink to see you created an excel spreadsheet of practical pruning experiences. Oooo i hope all you other folks out there casually reading this will respond with more information. especially also to pad up Miguel's database with more info from colder zones. only 9 entries! Is that a lot or a little? I don't know.. Just how many data points do you have in this little database of yours Miguel??

At any rate, it's finally raining here after 3 weeks. I pruned at just the right time. Oh yes, I meant to ask. Notwithstanding making this a you and me discussion Miguel, do you think your clematis rebloom because of an extended cooler weather in the fall? I can't imagine it is due to watering since hotter climates = more droughty. But many posters say they prune in july, and then clematis rebloom in sept. well why not mine? is it because of lack of sun? something chemical in the plant says shorter hours of daylight = start shutting down for winter? just some musings..

I'm going to give the pruning after bloom thing a try this year, as my clematis don't bloom again anyway. (It can't hurt, right?) I'm also going to try fertilizing them then. I hard pruned Silver Moon this March, and, while short, it is loaded with blooms & buds. Henryii got an unwelcome pruning from Mother Nature in April, & only 1 flower opened so far. It faded yesterday, but there is 1 new large bud & dozens of tiny buds forming. In past years, Henryii has bloomed for me only in May & June, so it will be interesting to see what will happen this year. The plant is so massive, I set up another trellis next to the original 1, but there are so many canes far from the trellises that I had to fold them back up & onto itself. I think I might just cut those off to see what will happen. I'm toying with the idea of graduated pruning next Winter/Early Spring, by cutting the vines close to the ground in front and leaving them progressively longer toward the back, which I will leave unpruned, to see if I can extend the bloom season.

18 data entries to date Kitova.

As for your question, which types are you cutting back and not getting rebloom on? There might be some that just don't respond well to that treatment. Also, where do you have them planted? Are they getting the same amount of sun as they normally do earlier in the season (sun lower in the sky as fall approaches)? Are you fertilizing them after cutting them back and keeping them watered?

The weather definitely cools down here after the main summer heat subsides, but I really don't think it is the weather that allows them to rebloom. Just my musings! LOL

Most of my clem are new last year. Some bare root, some babies, some year olds, some 2 years.

I want to try the cutting back, but a 6 or so year old Asao is the only ELF that has even started flowering, except for a few that were bought in bud this Spring. I think I planted them too deep.

I definitely will do Clair de Lune, as Cindy T is North of me. And I bought a lot of my 1 & 2 year olds from her last year, and a few when her nursery opened April 21.

It is sort of wierd that in some ways I want my clems to finish blooming, even before they start, so I can try the experiment.

Marie

I'm guessing your answer is going to depend on the genetics of the cultivar as much as zonal information. Winter naturally kills my Josephine (unknown origin) back to the ground, and she blooms almost constantly all season. But winter does the same to Kirigamane (unknown) and I have yet to get more than a small flush when it does bloom.

I cut back my Cezanne this year to the ground when transplanting, and it's up and budding (lanuginosa, fortunei and H.F. Young). I regularly prune H.F. Young (unknown) to the ground each year with good results due to its proximity to another type 3.

I treated Mrs. Cholmondeley (fortunei x jackmanii) as a type 3, and she's blooming fully at almost exactly the same time as last year.

Most type 2's of mine I want the new wood blooms, but as bloodlines get mixed, so do concepts of blooming on new wood versus old wood.

miguel, so your hypothesis is that it is not so simple as merely a longer warmer growing season that allows rebloom but specific light/nutrient/water conditions..? hmmm well right now, i only have one data point to give you - ramona from her post bloom haircut last year. i gave her a very severe 2/3 haircut last year and that could have some impact. i do not recall fertilizing with pellets/compost/liquid after pruning. i watered whenever it didn't rain for 2 weeks. ramona is planted right next to one of my multiblues, SSE facing with afternoon shade btw 1-4pm due to some big trees in our neighbor's yard, possibly in the fall they get less sun due to the angle of the sun.. also cultivar could very well be a consideration. ramona typically blooms at least 2-3 weeks later than my other group 2s... so i just pruned my multiblue today by 1/2 to see if it will rebloom this year. although the summer was late by 2-3 weeks this year so again that can throw the results. wow, this isn't going to be a very scientifically sound experiment - too many variables really. but sounds like fun nonetheless!

entling and eden, i'm so excited you're going to do this with me! eden i don't think it is possible for you to plant too deep.. and i know what you're saying about wanting them to finish blooming. when i pruned nelly and multiblue this weekend, i clipped off a few flowers/pompoms that were still in bloom in my rush to clean up the plants.. it almost feels as if my OCCD (obsessive compulsive clematis disorder) is wearing off a little..

I am probably 2-3 weeks behind you. My Multiblue started blooming last week. It is loaded with buds. I pruned it in early spring - cut the stems at around 1, 2 and 3 feet. I will cut it down by half when it finishes. This is it's 3rd year in my garden. It has never been cut back mid season although it will flower, but not as strongly as the first flush, until the first hard frost.

I have a 4 or 5 year old W.E. Gladstone that gets cut to the ground every year, but it always blooms early. It will pause for a couple of weeks, then start blooming again without being cut back, though not nearly as strong as the first flush. I have never cut it back mid season. I'll experiment on this one too. I should be able to prune it in a week or two.

Kitova, you are correct--way too many variable but the information is interesting.

I think I said that I didn't think it was a cooling that allowed rebloom. I do think that the amount of growing season that one has does have an effect on whether a clematis will rebloom or not. But I don't think it is a specific zonal requirement, but rather the individual growing conditions. I also think that perhaps specific cultivars may be better suited to rebloom after cut back than others. That would explain why some people in colder zones do get rebloom or at least an initial bloom if they are cut back in the spring and people in warmer zones than the cold zones can't get theirs to rebloom at all.

well it looks like michael in chicago has a few more datapoints for you miguel.

janet, i like the sound of your method of pruning 1 2 3 feet to graduate the blooms in height. i think that is what entling is thinking of doing. do you have pictures of your first flush? are your repeat blooms single blooms on new growth? i do want to note that my multiblues haven't ever rebloomed after their first flush. this is interesting to note because it means that other factors besides cultivar that are in play: most likely because i have never cut them back; but possibly also age of the plants (they are 3/4 years young); or perhaps due to my climate or feeding. goes to show that the same cultivar can have very different results in two gardens, and how hard it is to diagnose why. :P

i have another multiblue. albeit it is in a different shadier location, but i will try janet's 1/2/3 ft pruning method on it then compare the two..

oh shoot! i forgot, i have a third multiblue! it is in a sunnier location. maybe i should experiment with that one instead.

Kitova - I haven't take a picture yet. I finally figured out last night in a fit of boredom how to post photos. If I'm going to get a photo it will have to be tomorrow. Storms with high winds and large hail are in the forecast. I'm keeping my fingers crossed that the storms won't be as bad as they are predicting.

The second bloom on my Multiblue were singles.