Saturday, September 22, 2007

Sweet Autumn Clematis

©2007 S.R. Calef

There's probably no other fall flowering plant quite as popular as sweet autumn clematis. And there may be no other plant that has been the recipient of as many name changes as this clematis. Scientifically speaking, its original handle of Clematis paniculata seems to persist, although it's also referred to as C. maximonowicziana (I know... I won't even try) and C. terniflora. I'll stick with C. paniculata, thank you. Trained to arch across a natural pathway, this clematis is ideal for a number of landscape applications.

©2007 S.R. Calef

As the above close-up demonstrates, this clematis offers valuable late season nectar for bees, butterflies and other pollinators. Zone hardiness is 4-9 and it prefers full sun to partial shade.

©2007 S.R. Calef

Growth rate is rapid and although it can reach 30' in height, it is easily pruned and trained in a variety of styles. Flowers are borne on new wood, so an early spring pruning will control size. Bloom time is August and September, which is followed by seed production - rarely, seedlings are a little invasive. The twining stems readily climb across archways, arbors and pergolas.

©2007 S.R. Calef

Here we see sweet autumn clematis clambering over a rustic country fence. Because of its vigorous habit, it is often used to hide unsightly views. Wherever you employ this clematis, the amazingly sweet perfume will fragrance the late summer/early fall air.

©2007 S.R. Calef

This view of a single blossom reveals the delicate beauty... a simple, yet complex flower.

©2007 S.R. Calef

Spectacular against the bright September sky, sweet autumn clematis drifts across the landscape like freshly fallen snow. In spring, such a sweet tangle of vines is often home to the delicate nest of the hummingbird, providing dense protection, long before it blooms.

©2007 S.R. Calef

One more use? This is where that 30' height comes into play. Spilling down a hillside, cascading across ledge, sweet autumn clematis is an effective and fragrant answer to many a ground cover question. This a plant worth investigating - worthy of your landscape.


©Deb Lambert 2007

27 comments:

Julie (a.k.a. "MomMEE") said...

How far apart would you recommend planting Sweet Autumn Clematis along a fenceline for coverage? Thanks!

GardenAuthor said...

Julie ~ About 4-5 feet apart... they are strong, fairly rampant growers, so even at 6-8' spacing, they'll fill in quite well. If you're in a hurry for coverage, stay with the first suggestion.

Thanks for stopping by! ... Deb

Anonymous said...

I read last year about a native alternative to this plant, but I can't recall what it was. I prefer to use native speocies in my garden when I can, so do you have any suggestions?

GardenAuthor said...

Anonymus ~

Probably Clematis virginiana Virgin's Bower... blooms July to September, fuzzy creamy white flowers, climbs to about 20'and thrives in sun to partial shade. Native to the eastern states, west to Kansas and north into Canada. Hope this helps... and thanks for the visit! ~ Deb

Anonymous said...

I have an 8 foot wide and 16 foot long pergola that I have started 2 sweet autumn clematis vines on. Each are on opposing corners so they can grow and meet in the middle. I have had this for two years now and it has not covered the area like I thought. It also seems like I have to keep training it. I just saw where pruning might be needed....as I have not pruned this vine. It seems that would defeat my purpose in coverage. Could you give me some advice on how I can achieve the coverage? Thanks so much!

GardenAuthor said...

Anonymus ~

A little early spring pruning, cutting back by about 1/4-1/2 of the height, would have encouraged fuller growth - generating more climbing stems. Secondly, there is the spacing of plants and while they would eventually fill in, one on each corner of the structure would hasten the coverage.

I actually have a similarly sized metal gazebo/arbor structure and have four vines planted (2 honeysuckle, a kiwi and a trumpet vine). Last year was the first time, with vigorous training and tying, that I started getting coverage... after a six year wait. It was also the first year I started sprayed the foliage with Neptune's Harvest fish & seaweed fertilizer. Big improvement this year!

Your autumn clematis needs lots of training and tying, as it progresses. They need their tops in the sun and roots in the shade. Patience, organic fertilizer (and a little lime, as they prefer a neutral to slightly sweet soil) and some early pruning next spring (they flower on new wood) should get you the coverage you need... and maybe two more plants, for faster coverage should solve the problem.

Thanks for dropping by... Deb

Anonymous said...

I have read that I need to plant something to shade the roots of my sweet autum clematis, but I have no idea what specifically I should plant. Do you have any suggestions? Thanks!

GardenAuthor said...

Anonymous ~ Asarum europaeum (European wild ginger), creeping thyme (try woolly or caraway), Irish moss (Sagina subulata), Tiarella (foamflower - North American native), Waldsteinia (barren strawberry), cranesbill (perennial Geranium), ground phlox and perennial pinks (Dianthus species) are all good choices.

A 2-3" layer of compost or shredded bark mulch will also keep the roots cool and moist, while providing a few extra nutrients - just avoid direct contact between the mulch and clematis stems.

Thanks for the visit! ~ Deb

Anonymous said...

I am trying to keep several clematis plants along a fence symetrical. when should I stop triming the vines to insure they will bloom? Should I trim in a special way?

GardenAuthor said...

Anonymous ~ Since Clematis terniflora flowers on new wood, the best time to prune is early spring, just as the vines emerge from dormancy... they can actually be cut back to about a foot each spring. This encourages lots of fresh growth, on which will be borne an abundance of blooms.

If hard pruning is not done annually, or if you wish to retain more of the mature height, then pruning at that time to remove approximately 1/2 of the old wood will encourage vigorous new growth. Cutting into old, woody stems that are not pruned back on a regular basis, will not result in strong regrowth. Always cut back, on a sharp diagonal angle, just above a live bud.

You can do some light spring or early summer pruning to further shape the vines (at that point, prune above a lateral shoot or bud), but waiting too long will result in the loss of some of this season's flowers. Early July is about as late as I've ever pruned without diminishing flower display.

Here, in New England, my phosphorus-poor, rather acidic soil is amended each spring with Plant-tone organic fertilizer, rock phosphate and pelletized lime. The combination of proper pruning (and timing of same), plant food to push out new growth (clematis are fairly heavy feeders) and quick releasing pelletized lime (changes pH in about 6 weeks) will maintain vigorous growth and result in good bud set.

A lighter July 4th feeding with just the Plant-tone is also applied. During the course of the growing season, I also apply Neptune's Harvest fish & seaweed liquid fertilizer to the foliage - every 14 days, when I foliar feed adjacent plant material.

Hope this answers your questions. You might be interested in a little garden show, produced locally in Newburyport, MA - hosted by myself each Sunday from 8-10:00a on WNBP 1450 AM. We live-stream the entire show at www.wnbp.com. Give a listen and drop by anytime with your questions! ..... Deb Lambert, host of "The Corliss Garden Show."

Frank said...

How many hours of light does C. paniculata need? I've got a small birch about 12' high I'd like to grow the clematis on, but it gets morning sun only and dappled shade in the evening. Also are the water requirements such that the birch would make an unhospitable host?

GardenAuthor said...

Frank ~ Full sun for Clematis paniculata (C. ternifolia)... although I've grown it in AM sun until 2 PM and in strong PM sun, until sunset... both fared well.

Even though clematis vines can clamber over many shrubs and trees at no detriment to the host, the very dense foliage of the autumn clematis is too much competition for the small birch, cutting off necessary light. In addition, this fairly rampant grower sometimes need hard pruning - rather difficult once it has twined its way up through the tree.

Feel free to call in any Sunday from 8-10:00 AM (eastern time) to The Corliss Garden Garden Show... live streamed at www.wnbp.com, hosted by myself.

Have a great gardening day! /Deb

c said...

My sweet autumn clematis does not smell even a little. What am I doing wrong? Do I need to get a second one to get the smell?
Thanks for an information.
Chris in Nebraska

GardenAuthor said...

"c" ~

Check the foliage... if the foliage margins are toothed, you have an American native Clematis virginiana (Virgin's Bower)... flowers are a bit smaller, very prolific but have no fragrance... I grew one years ago and found the height and coverage about the same. Sometimes sold as SAC.

True SAC has smooth leaf margins and lots of fragrance. Whether you call it Clematis terniflora or C. paniculata, SAC (native of China, Korea & Japan) is the right one for amazing fragrance.

Deb

Anonymous said...

Hi! I have planted in my backyard what I was told are Sweet Autumn Clematis. They look just like the pictures you show and they smell beautifully.
My concerns are that the main blooming time is June and they don't seem to grow past 8 feet. I live in Northern Virginia and the plants are about 5 years old.
Could these be a different species? Or is there something I should do differently? I have been pruning them in the spring to about 18 inches.
Any ideas or suggestions would be greatly appreciated.
~Al

GardenAuthor said...

Al ~ It is possible that you have another species. I once purchased an alleged Sweet Autumn Clematis, only to discover it was not... earlier blooming, not much fragrance and smaller blossoms...undoubtedly Virgin's Bower (see above comment addressed to "c").

If yours has smooth leaves, it probably is SAC (C. paniculata). I'm guessing you're cutting it back too hard, at 18 inches (although this is often recommended),to attain significant height... left on their own, they will reach 20 feet. Cutting back by about 1/4 of the overall length, results in more branching, more new flowering wood being produced and more coverage being retained. Earliness of bloom certainly might be attributed to a difference in species, but variables like location or a season that breaks early, may account for early bud set and flowering. In the past, I've noticed that sudden, early onset of hot summer weather prompts earlier flowering.

If you read through the above comments, you'll find pruning and feeding recommendations, which also make a big difference in flowering and overall health.

Hope this helps... Deb

Anonymous said...

Hi! I planted a Sweet Autumn Clematis to grow up our pergola last year. It indeed had vigourous growth (it got to about 14') and has great flowers.

However, this season I am not seeing any new growth on the old vine, but it has started to shoot from the ground again. Is this normal?

We live in Ellensburg, WA so it went through a harsh winter, but the new growth looks very health.

Cheers! Tom

GardenAuthor said...

Tom ~ I think you've answered your own question, since a particularly harsh winter can either cause top-kill of the woody portion, or even death to the entire vine. I actually lost one after a severe winter.

The fact that you're noticing strong shoots from the base is a good sign and to further encourage this, cut back any dead portions to live wood. A feeding of organic, granular fertilizer will help push that new growth along.

Be sure the soil is sweet enough... our New England soils are notoriously acidic and annual liming is often indicated in this area. While clematis tolerate a wide range of soils, they perform best at 6.5 pH.

Lastly, remember to supplement with rock phosphate to strengthen roots and boost bloom production. Much success with your Sweet Autumn Clematis! ..... Deb

Anonymous said...

I'm thinking of planting some Sweet Autumn Clematis along a waist height chain link fence. It looks like a gorgeous vine and if it has a fragrance that's a definite bonus. I've read quite a few online comments elsewhere that talk about how invasive this plant can be. Others claim it randomly roots in their lawn and can pop up all over the place. How problematic is it? I live in Indiana, zone 5. Is silver Lace vine a good choice to cover a fence, or is SAC better in your opinion. I really enjoy all the posts on this site. Susan

GardenAuthor said...

Susan ~

Silver Lace Vine would win the invasive award around here. While it does grow quickly to cover unsightly fences or sheds, it has risen to the top of many state watch lists, and may be banned in some. Closely related to our Japanese Knotweed/Japanese Bamboo (P. cuspidatum), this Polygonum is a rampant grower, requiring an even firmer grip on the pruners than SAC! It's a great bee attractant, but SAC is, as well... and more fragrant.

In our Zone 5 gardens of Massachusetts, Sweet Autumn Clematis does not usually display an invasive nature. It self-seeds, which may account for those lawn volunteers. The following advice will enable you to control its sometimes exuberant nature.

Suggestions for pruning and maintaining SAC along a fence ~ Since Clematis paniculata flowers on new wood, the best time to prune is early spring, just as the vines emerge from dormancy... they can actually be cut back to about a foot each spring. This encourages lots of fresh growth, on which will be borne an abundance of blooms.

If hard pruning is not done annually, or if you wish to retain more of the mature height, then pruning at that time to remove approximately 1/2 of the old wood will encourage vigorous new growth. Cutting into old, woody stems that are not pruned back on a regular basis, will not result in strong regrowth. Always cut back, on a sharp diagonal angle, just above a live bud.

You can do some light spring or early summer pruning to further shape the vines (at that point, prune above a lateral shoot or bud), but waiting too long will result in the loss of some of this season's flowers. Early July is about as late as I've ever pruned without diminishing flower display.

All things considered, SAC is the better choice. Much success with your chosen vine. Glad you enjoy the site... try our weekly garden newsletter 'GardenAuthor@CorlissClips' on blogspot for even more info.

Deb

Anonymous said...

I did not recognize the "volunteer" that appeared, spilling out over my driveway with great puffs of fragrant little white flowers several years ago, but decided it was a keeper, nonetheless. Checking around town (mid-Kansas) I saw examples almost everywhere. Undoubtedly it was planted by birds eating the seeds from some of those vines. I do not find it particularly invasive and have trained it to mask a picket garbage can enclosure. I look forward every year to its beauty. I'm going to try propagating it from seed this year.

GardenAuthor said...

Anonymus ~ Nice that you're enjoying that volunteer, putting it to good use as a screen. Mine has never been overly aggressive or shown signs of an invasive tendency; however, I mentioned the possibility in the article, since I know of several plantings that have not been so well behaved. This is more often the case in warmer climes than our Zone 5/New England area.

A note about volunteers: As is so often true of plants raised from seed, they are likely to differ from the parent. In this case, the sweet fragrance is likely to be minimal or non-existent. The only way to be assured of fragrant progeny, is to propagate by vegetative means... cuttings or soil layer.

Great plant, as far as I'm concerned! Much success with yours... Deb

GardenAuthor said...

Anonymus ~ A followup comment... Your question and my reply will be covered in the "You Talk" segment of our local garden center newsletter, 'GardenAuthor@CorlissClips' (on blogspot.com). As we prepare for the upcoming growing season, gardeners may be seeking such exuberant, fragrant coverage as the sweet Autumn Clematis.

Thanks for commenting... Deb

Michael Bacon said...

This plant is the bane of my existence in piedmont North Carolina (along with Japanese Stiltgrass). I'm not sure where it was originally, but it's invaded my rain garden, my neighbor's fenceline, the areas around the foundation of my house, and all over my yard. Cutting it does nothing to deter it, and the roots establish so deeply that permanently getting a clump requires a 12 inch deep hole with a shovel. I'm not sure if the RoundUp I used was just ineffective, or if the plants were just replaced so fast by other climbers that it didn't matter. What's worse, mowing over it releases something that's very irritating to my eyes and nose.

My guess is that hard freezes ( <10 degrees) knock it back a bit, but in the city in North Carolina, we rarely see those. So if you're in the northeast, you're probably fine. Down here in the southeast, I have to recommend everyone avoid putting this in at all costs.

GardenAuthor said...

Michael ~ It's true that in our Zone 5/6 area, north of Boston, we have few problems with this plant's inherent invasiveness. I've spoken with other gardeners in southern zones, who have experiences with SAC similar to yours.

I wonder if you might have more success with an herbicide containing Triclopyr... Roundup Poison Ivy® combines this with Glyphosate and Triclopyr is the only active ingredient in Ortho MAX Poison Ivy and Tough Brush Killer. Used as a foliar application, or painted, undiluted, onto freshly cut stumps (using the frill method), either of these non-selective controls might prove more effective in eradicating what is obviously an ill-mannered backyard resident.

On behalf of our Southern audience, I thank you for your perspective!

Deb

Anonymous said...

Will Sweet Autumn Clematis grow in shade? I have a 25' section in my backyard that is shaded by +40' tall cedar trees and a +100' tall oak tree that provide total shade all day. Their size has left an openness underneath them that I would like to fill in to hide the road that I can see. I was thinking about snaking a 6' tall green wire mess fence through the cedar trees and planting the Clematis along the fence. Will Clematis grow in such shade? Will it bloom?

GardenAuthor said...

To Anonymus...

Like all clematis, SAC prefers it head in the sun and roots in the shade and although it may tolerate a bit less than full sun, its performance in too much shade will be disappointing. Limited (if any) flowering and often mildewed foliage ensue in such low light and this will be true for any flowering plant forced to grow in such a situation.

Although Hydrangea petiolaris will accept some shade and still produce blooms, it does require some sun, especially if good flower production is expected. Parthenocissus, both Virginia Creeper and Boston Ivy (this one more so) are tolerant of some shade, but survive at the expense of their normally brilliant fall foliage.

Fiveleaf Akebia is quite shade tolerant and is another plant grown for its foliage and ability to provide screening. Trumpet Vine (Campsis) is somewhat shade tolerant (not for total shade), but needs a fair amount of sun to flower. English Ivy is an evergreen vine or groundcover, but I doubt it would be happy on an open, mesh fence, since it performs best on the solid support of rock walls or brick structures (however, the rootlets can be responsible for mortar damage).

Yours is not an easy situation and you need to keep in mind that some shade tolerant plants require moist soil, while others perform best in dry shade. There is always competition with the trees for moisture and nutrients.

Some vines are ill-mannered and so aggressive (with many attaining heights of 30' or more) that they will climb high into the trees, seeking sunlight. Unfortunately, they sometimes girdle trunks and branches with their main stems and as the vine foliage becomes ever more dense in the tree canopy, it begins to exclude light from the tree foliage, leading to decline.

Just be careful to make a wise choice for your difficult, shady situation... sometimes an attractive wooden fence is a more practical way to obtain privacy.