I have a huge SAC growing in the PNW as well. It produces thousands of flowers every fall and I also have never had even 1 seedling. I wonder if our fall nights are too cool and the seed doesn't ripen. It has never been invasive for me. I just love mine and wouldn't be without it. Karen

I'm just wondering if they've correctly identified the vine - one would hope so before reporting it as a pest! Clematis virginiana bears a rather close resemblance to SAC and has naturalized freely throughout the east coast and midwest and is definitely considered invasive, as is C. vitalba here on the west coast. I'd list either of those as seriously problematic species long before C. terniflora. And both could easily be mistaken for SAC without careful study.

It would not surprise me if they did mistake SAC for the other two.

I don't know which one I have - always assumed it was SAC, b/c it is VERY fragrant in the fall. It is the most invasive plant I can imagine. I generally appreciate some degree of invasiveness, but this is ridiculous. It pops up everywhere and is impossible to get rid of as the roots are very deep and stubborn.`Really, as I said, I don't shirk from mint, honeysuckle, violets, virginia creeper, morning glory, bristly locust (my fave), or even trumpet vine, but these are far worse. They are so vigorous that they just swallow up every cultivated plant they can get their tendrils on.

Plus, the worst part of it is that if you have fall season allergies, I really think that all that prodigious pollen production is just the worst. I kept a gigantic, gorgeous one climbing on my house for several years, but it just got to be too much last fall. Had to have DH rip it all out one morning before work because I was just miserable - dumb to have it right by my front door! My kids loved it, though. They are beautiful even when not in bloom with all that healthy foliage and superior climbing ability, imo, than the large-flowered clematis.

I had a problem with SAC being invasive in my zone. I had them coming up every where and even the small seedlings were difficult to pull up. They had a very deep root system on them and would keep coming back. Round-up hardly phased them. I would have to use a garden trowel or shovel and really dig them up by getting all of the tap root system. I will never grow it again, despite it being lovely. It just got too huge and had too many babies.

I totally agree! SAC is VERY invasive in my growing zone!! Yes, it is beautiful when in flower, but the rest of the time the seedlings tend to sprout up everywhere in my garden and it's extremely difficult to erradicate. I wish I had never planted it years ago....it really helps to do your homework & read up on each variety BEFORE planting it in your garden. That will save you a lot of headaches in the future.

I will gladly adopt all those s.a.c children. :>)

Ladies, you are in the south, which has a significantly different climate and growing season than does the Northeast. I would expect to see free seeding of a variety of species clematis in a very temperate climate with hot summers. And there is a huge difference between a plant that self-seeds freely and one that is considered invasive by the USDA Forest Service under their definition.

I still think they misidentified the vine. There have been no previous reports of Clematis terniflora naturalizing widely.

I've got what I believe is SAC, and it does re-seed, but, I simply dig up the seedlings (which is not difficult), and, I usually pot them up and give them to friends who admire the plant. I look forward to finding a chance seedling.

I did find that, when I gave SAC very good growing conditions, it was way too aggressive as a companion for a rose on an arch. So I dug that one up and gave it away. I think it does well on a fence off by itself somewhere. This year I intend to let one climbe a tree.

Robert

O.K. - Now you've got me attention. . .at the bottom of my
garden, there is a grand speciman of C.terniflora, planted
some eleven years ago. If there's an invasion coming, it's
certainly slow getting started - this vine rambles along a
50'long fence, with fertile soil on both sides, and in all
these years, not a single seedling. . .and this plant is the rooted cutting off another specimen which thrived in my
previous garden in New York City, again with nary a seedling. . .

So: your theory, gardengal, about incorrect identification
certainly sounds plausible. . .in any event, I am so intrigued by your discovery, that I'm going to do a little
sleuthing with contacts at the NYBotanical Garden and
Dan Long at Brushwood Nursery, our clematis guru in these
parts.

I shall report back here, anon. . .

Carl

Six Days Later:

Well, I'll be darned. . .the consensus from everyone con-sulted thus far is that, yes, C. terniflora (our lovely
SAC) is invasive, but there were a lot of "Could be" or
"prone to be" or "possibly" invasives. . .

All of which leads me to think that this is going to be
one of those HUGE grey areas, another case of "Grower
Beware!", or make that "Grower Be Advised". . . The seems
that the longer I garden, so much garden information is
highly anecdotal (of course!). . .by that, I mean, if all
we ever hear about (from each other, from the pros) are
the 50 negative experiences that people have with a plant,
and never the 900 positive experiences (or neutral), then
what impression does that leave with the questioner?

Good example: for years I have heard people rant and rail
against Aegopodium podograria (Bishop's Weed)- under a
maple in my garden is a gorgeous planting of said evil
weed, the envy of all who see it (especially in bloom!)

So where does all this leave us? With our ears to the
ground, I guess, and continuing to weigh all the info we can find about plants. . .meanwhile, my C. terniflora will
continue to adorn my back fence, and the clematis guru who
admitted that "Yeah, it can be invasive. . ." continues to
feature it on his website, as do most of the nurseries I
deal with!

Thanks, gardengal, for inspiring such interesting reserach.

Carl

I grew up just north of Asbury Park, NJ. We had one of these plant itself in the rose hedge along the driveway, and the scent in late summer is heavenly. However, the birds "plant' the seeds all over the place & I spent my teens trying to pull up volunteers from the rest of the yard. And the original totally took over the drive area. Yes, it is invasive, at least in Z6 area. I still love the scent though.

I wonder if some of us have a sterile type of SAC. I have never seen a seedling from mine.

I have it...like a bad disease....everywhere...even in my lawn. I've tried the strongest poisons i can find (even experimented with diesel)...nothing kills the root. My biggest problem is...when its mowed it produces a toxic fume that burns the eyes and throat. My next plan is to burn with a torch and blast the root area...I have thousands of starts or different sizes...everywhere...my suggestion, plant sweet olive if you need olfactory stimulation.

Clematis...invasive? Oh my god!!!

We have never had a Clematis planted on this property, yet it is among the worst invasive problems I have....not only here, but throughout this entire wooded valley! It has infested the wooded park next to me, and down the road for at least a mile, following a creek.

Until I ID-ed this evil aggressive monster I called it "blanket vine," for it doesn't wrap itself around trees like honeysuckle or grape vine, but instead shoots straight up and smothers trees with blankets of endless fast-growing leaves and tendrils. I thought maybe it was kudzu! Certainly it must be nearly as bad.

It pops up EVERYWHERE! And there seems to be no getting rid of it! I spend a fortune on Round-up every year....it hardly balks. In 5 years I've gained no ground in eliminating it. The best I can do is continually fight it back.

In less well-tended roadside areas it runs rampant. In late summer when the fizzy white flowers appear, you can see it everywhere, smothering trees, and sadly no one is doing anything about it. There seems to be very little that CAN be done about it!

So PLEASE do your neighbors, the woods down the road and the whole world a favor and DO NOT BUY AND PLANT CLEMATIS!!! And please, pass on the word!!!

I know that SAC is a problem here in my area. In late summer, you can drive down I-95 (or any number of local streets and highways) and see enormous swaths of SAC completely covering stretches of shrubs and small trees.

As someone who gardens for a living, I can also tell you that I spend considerable time pulling SAC vines from wood's edge properties and garden beds - in gardens that aren't intentionally growing SAC.

I've been hearing of the ecologically damaging qualities of SAC for some time.

A web search for "invasive sweet autumn clematis" will get you quite a few hits. Some are casual discussions, but several are official and/or scholarly/university websites.

Here is a link that might be useful: Invasive SAC

I'm glad this old thread has been resurrected as there seems to be some strong responses and even some that are alarmist in their intensity :-) And they need to be addressed.

The invasive potential of ANY plant has a great deal to do with its location and growing conditions. It is unfair and inaccurate to assume that because a plant has invasive tendencies in one area and under one set of growing conditions that it will react in the same manner everywhere else. The reason I posted this thread initially is because it surprised me to learn that SAC was considered invasive in specific locations - it is most definitely NOT invasive here in the PNW. In all my years of gardening, both personally and professionally, I have never seen a single spontaneous SAC seedling in this area. Nor is it considered even slightly problematic by local authorities. I am sure this is a locational thing, as other plants with a strong reputation for invasiveness elsewhere - Japanese barberry, nandina, burning bush, etc. - are not the slightest bit invasive here either. Our cool summers just do not allow for the ripening of seeds that can create the problems. We have other invasive plant issues not necessarily shared by other parts of the country, but these are not among them.

It is also important to remember that the term "invasive" as it correctly applies to plants/insects/animals is limited to those of non-native origins. By definition, a native plant or other species, regardless of how rampant their spread or proliferation might be, is not technically considered "invasive". And this can lead to confusion......the clematis 'problem' described by sunleafmoon in MO may only be that of the native Clematis virginiana, which is widely naturalized in that area. And which is easily confused with C. ternifolia by those less familiar with the distinctions between the two species. Or it could also be Clematis vitalba, another very similar in appearance non-native that has become problematic in various areas of the country, including the PNW. While the differences may be inconsequential to the home gardener who must deal with the aggressive spreading, only the two exotic non-natives (terniflora and vitalba) are considered of environmental concern and therefore potentially "invasive".

And it is certainly inappropriate and inaccurate to lump ALL clematis under the label of "invasive" and to caution against planting. That's just taking a small problem to extremes.

SAC certainly is not invasive in my yard as I have never seen a seedling. Actually, it was planted about 3 years ago and I am wondering when it will appear as I have seen no sign of growth but I realize it is slow to appear.
It was just beautiful last year !
Lois

I had to move to get away from Aegopodium podograria (Bishop's Weed)!

Sorry, could not resist. ;)

I've never grown SAC so I can't comment. I have talked to people on another online forum who had SAC and Clematis virginiana confused. I have also seen eBay auctions where the seller had them confused....

You know, gardngal48 is right. Plants that may be invasive in one place may not be in another.

I understand butterfly bush is so invasive in some parts of the country that none are allowed in gardens. Mine never leave the area they are planted.

In Alabama, you cannot buy water hyacinth because it is invasive in waterways...I have had it in my pond (not now) but would have to go out of state to get it. (My pond does not connect to any other water. I can't imagine an invasive clematis, but had already decided not to risk SWC just because I live in the south. I appreciate the input

kay

I'm sorry if I seem "alarmist" to those who apparently love Clematis terniflora, but to me it is like hearing someone defend kudzu. And it isn't just me who is alarmed by its invasiveness..... Clematis terniflora is banned in 6 states, unfortunately not including my own. If I could post pictures, you would see why. What it is doing in this valley is horrendous, and if there is a way to control it, please, please tell me how. I am fairly certain it is not native, for I have never seen a native plant of any kind this aggressive. It needs to be discouraged before it spreads even further.

Why take a chance on its invasive potential in your area? Once you find out that it is in fact invasive, "Oops, sorry" won't erase damage done. I'm sure whoever planted it near here probably was not thinking of how the seeds would fly and seriously infest land far beyond their property and beyond their control.

Now that you folks know the damage that can happen, I hope your gardening precept will be, "First do no harm." There are any number of gardening alternatives to clematis terniflora. Please choose them.

Clematis do not spread by runners like kudzu.

It's easy to control SAC. Just cut the plant down after blooming before the seeds ripen. Easy. To eliminate the plant, dig it out or cut it back to a couple of feet, spray with a systemic herbicide and it's done.

SAC isn't invasive in my area either.

First, sunleafmoon, you never identified your problem as Clematis ternifolia, just as "clematis". And in very strong terms :-) Being that broad in your statements with no qualifier and with such emphasis, is it surprising you were considered alarmist?

OK, so you have issues with SAC and it is a confirmed problem in certain areas. But not everywhere. Certainly everyone should use caution when it comes to including potentially invasive plants in their garden but it is very easy to check with local authorities to see what is or isn't considered an invasive species in your specific area. To blanketly condemn SAC for everyone, or in your case, give the impression that ALL clematis are invasive, is inaccurate and unfair.

I'm sorry, gardengal, but you began this thread with reference to Clematis terniflora. I added to the thread with the understanding that I was referring to the same species.

And no, it is not easy to control. My parents owned this property before me and no one has ever planted it here, yet I have literally hundreds of Clematis terniflora popping up every year. They pop up in the lawn, they pop up in the woods, they have blanketed the trees along the road through the valley here and in a neighboring park, following a creek. As it has gone largely uncontrolled along the road, I suspect new seeds continually reseed my property. Not that it is easy to get rid of what is already here. Trying to dig up noxious invasives has given me carpal tunnel syndrome, so I can't use that method for hundreds of Clematis terniflora. And Roundup causes it to wither and inhibits new growth for a short while, but a sprayed plant comes back. It is not "done."

With global warming, the problems of southern climates are bound to head northward. With Clematis terniflora banned as invasive in 7 eastern and southern states, there is good reason to be concerned. Would that someone had been "alarmist" when Japanese honeysuckle, shrub honeysuckle and kudzu first went out of control. Then maybe we wouldn't have the destruction of natural areas we have today.

Rather than defending this plant and questioning my experience, I would hope that others might apply a gardening principle of "First do no harm." And it would be of great benefit, I think, if Gardenweb added a a forum topic on Invasive Plant Species, so the community of gardeners might be able to track the regional progress of invasive non-natives, in order to promote abatement and control. This would not only benefit our own interests, but those of the larger community.

I was pointed here by someone from the PA Gardening forum. Very interesting discussion. I'm a biologist/plant person/land manager/gardener, but I'm not sure I could casually discern all the various Clematis species, and it seems like it could make a difference. I have seen a wild growing clematis only once here in the Allentown area, and I was told it was "wild clematis" but since I had never even heard of that, I didn't take much notice of the plant. I've seen the native clematis at a native plant nursery but I still thought at the time it was the smelly one.

Then, I saw some growing on my cousin's pergola and loved the flowers and smell. I didn't realize at that point that there was a native "wild clematis" and an asian species that was also casually called "wild clematis." Then last August I noticed my neighbor up the alley had some growing on her back fence and it seemed to be taking over that corner of the alley. But keep in mind that we also have "wild morning glories" that grow up around almost every plant going in the neighborhod if not constantly inspected. They seed and spread like the devil himself! What I've been passing may be a conglomoration of the two. Which is the most invasive culprit, who can tell!

I can see how someone not trained in plant ID could casually mistake "wild clematis" for honeysuckle or multiflora rose at a distance. I'm not saying anyone here did that by any means, I'm just saying that anecdotal reports on Web boards without oversight could have that factor in them. I am most interested in your experience Carrie, because it is closest to where I live. Allentown is zone 6 but could be getting more and more like zone 7 as time goes on. There is a general idea out there in the natural science world that plants are becoming more "invasive" due to many global climate change factors. It's not just temperature that is changing, soil conditions, the air, the whole web of species in many ecosystems is slowly unraveling, leading to cascading events . . . I totally agree with the "do no harm" idea in theory, but in practice it is harder to apply. Which is worse, planting a native plant that vectors pests and requires constant chemical upkeep, or a pest free non-native that might get invasive, but only in certain circumstances. Neither is a very good option. But it's getting so there are fewer and fewer viable options for maintaining healthy gardens.

I'm also wondering about the idea of the seeds being spread by birds. That is a definate in multiflora rose and honeysuckel. But the clematis seeds seem so dry. I would think they would be wind blown. So it's hard for me to discern how much my experimenting with planting a Clematis ternifolia in my yard will contribute to the massive problem of invasive plants. It's been my experience that first comes the habitat disruption/stress, then the weeds. If we continue to disrupt and stress habitats, invasiveness is inevitable. And believe me, I've spent my whole life combatting garlic mustard, purple loosetrife, barberry, stilt grass, phragmites, multiflora rose, honeysuckle, english ivy, euonymous . . . the list goes on and on.

I'm not going to plant it at this point, I'm just frustrated at my increasingly limited options for my row house, tiny urban yard.

I for one am thrilled to see my SAC appear as I thought it was a goner. In fact, I was ready to dig and plant another one in its place but I just noticed one stem comming out of the ground so know others will follow. It's a 3 year old clematis and I really like it. It was very pretty last summer and when it got a little too tall I just pruned it. Never has been invasive for me but it might be that I am in zone 4 with really cold winters.
Los

It is very disheartening to return to this thread and read the unwillingness of some gardeners to give up this highly invasive species. I imagine the same initial reaction to Japanese honeysuckle, shrub honeysuckle, kudzu. I am not a professional botanist or horticulturist, but I am a naturalist with basic skills in plant identification. I can assure you, I am not being an alarmist. Perhaps those who think so would like to come to my property and try getting rid of this invasive species they think is no problem? I've tried everything myself.

Please take this warning seriously, if not for yourself, then for your neighbors, your parks and for the local environment. There is no end of lovely species you can plant as alternatives. Again, please let your credo be, "First, do no harm."

I'll again put my 2 cents in: I spent a good portion of today pulling & digging SAC seedlings from a garden in which I was working. Removing SAC, either by digging or using herbicide when the plant is too big to dig is a part of my job in the Philadelphia area, especially those gardens adjoining park land. I know the difference between C. terniflora and C. Virginiana. I have yet to see C. Virginiana growing wild in my area, but SAC is all over.

I have what I think is SAC, could someone please tell me where I can see the foliage of this vine? Previous owner planted it by other clematas and I would like to get rid of this one and at this time I don't know which is SAC.

There is a close up of a leaf near the bottom of this page. And on this page there are pictures you can click on to enlarge.

Other than the leaf shape and the Japanese vine's propensity for invasiveness in some areas, it's hard to tell them apart. And I've found more than one source that assigns the common name of sweet autumn clematis to C. virginiana, which seriously confuses the issue.....cuz they both bloom late season and are mildly fragrant.

Check the photos at the bottom of the attached link: C. terniflora, the invasive SAC, has rounded, untoothed leaves. C. virginiana (and a number of other, late blooming native species) has coarser, jagged or toothed leaves.

Here is a link that might be useful: terniflora versus virginiana

I have a 2 yr old SAC and it has never spread for me yet. I absolutely love it!

Def not a problem here in northern michigan either, must be the cold. Brrrrrrr....

It's been a few years since I last posted on the clematis terniflora thread, so I thought I should provide an update. The situation here has only gotten worse.

In the area by my creek, approximately a half acre of land, I'd say there is hardly 2-3 square feet without a sprouting clematis vine. It is not the native. I know the difference.

It was never planted here, apparently it drifted down along the creek. It's infested a mile long valley and there seems to be no getting rid of it. It blankets trees and smothers them, cripples saplings and chokes out new growth.

It can't be pulled, it roots too deep or pervasive to dig out (on my property I'd have to dig up a whole half acre!) and even full-strength RoundUp only knocks it back temporarily. It just keeps coming back. The only way I've been able to thwart it is to continually mow, but some places can't be mowed, and besides, I wanted to go natural.

Given the endless labor I put into fighting this infestation, not to mention the cost of Roundup, it really pisses me off that people would be so casual about buying and planting this extreme invasive. I'm thinking about taking a video or inviting a state official to see my case, in hopes of supporting a ban in this state.

I have to fight invasive honeysuckle shrubs, honeysuckle vines, euonymus, English Ivy and vinca, but I'd say clematis terniflora must be about the most godawful invasive of them all.

I feel as if I have a different plant than those so damned as horribly invasive plants! My SAC is 5 years old and quite simply gigantic! every year I get what most people have never seen in height and width as well as too many blossoms to count. It looks like snow it is so profuse and thick with flowers. It is fragrant and lovely and easiest the favorite plant I my yard. Not a single solitary seedling, ever. unless this happens later in years, I see no sign of invasiveness. And I prune it down in the spring so the plant has plenty of chance to seed if it could.

I agree - my SAC has never produced one seedling and I've probably had it 10 or 15 years.