By: Becca Badgett, Co-author of How to Grow an EMERGENCY Garden
Today’s trend of using vertical space in the garden includes the use of a number of climbing and flowering plants. One widely used flowering specimen is the clematis, which may bloom in spring, summer, or fall depending on the variety. The diversity of plant types may leave you wondering when to prune clematis. Complicated instructions for pruning clematis vines can be found on the web, but many gardeners desire a simpler means of instruction. Follow these tips for pruning clematis and you will never lose a clematis bloom again.
Before you get started, there are a couple tips for pruning clematis that you should know:
If you prune clematis immediately after bloom time is finished, you won’t have to worry about removing next year’s flowers. Prune clematis for shape at this time, removing up to one third of the plant, if needed.
Avoid removing woody stems, if possible. Clematis pruning groups include those that flower on new growth and those that bloom on last year’s woody stem. Once you’re familiar with the bloom time of your clematis, you will be able to prune the vine before buds begin to develop.
When deciding how and when to trim clematis, don’t remove a developing bud. If you see buds developing when pruning clematis vines, you may be pruning at the wrong time.
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Properly pruning clematises will yield the maximum quantity of flowers by stimulating new growth. Pruning keeps the more vigorous vines under control. If not pruned, these large plants can literally tear down almost any support with their sheer weight. Keeping vines pruned brings flowers down to eye level rather than at a top of a tall plant. And if you have one of those mountains of tangled stems, pruning allows air and light to circulate through the leaves, reducing moisture that can cause diseases, and also tidies up the entire plant and displays the flowers to their best advantage. Clematises can live up to 50 years, so we want to take good care of them.
It’s obvious, therefore, that all clematises need to be pruned. Almost everyone knows that there are three main groups of clematis, with three different pruning techniques. Don’t let this worry you because it’s not as difficult as it sounds.
Example of a top-heavy vine (Duchess of Albany, Group 3). Incidentally, the rabbits chew this one down to the ground every year!
Before we find out more about the three groups, there is something that every new clematis needs. Very early in the first spring after the year you plant them, all types of clematises need to be cut back to approximately 12 inches from the ground. I know, it’s really hard to do because everyone wants to see the flowers, but doing so will make the root system stronger and promote branching and new stems from underground, making the entire plant bushier and healthier. So that means that you’ll lose your flowers the first year on some clematises, but it also means that you’ll have many years of more flowers than ever. That sounds like a pretty good trade off to me! If you don’t do this, it won’t kill your vine, but you will be very disappointed when you end up with one or two wimpy vines with only a couple of flowers. Then you’ll probably end up cutting it back anyway and losing even more time in the process.
Pruning produces more flowers.
Let's take a look at the three pruning groups. Every clematis has a pruning group assigned to it. If you purchase from a reputable nursery, that information will be included on the tag or on the nursery's website. If it isn’t, you can find the pruning group for each cultivar right here in our ATP database. Once you know the pruning group, it’s just a matter of following the information for that group.
Group #1: These are the early-flowering and evergreen clematises, and the group also includes the alpina, cirrhosa, macropetala and montana species. They flower on “old wood,” which is growth from the previous year. Don’t go crazy pruning this group. Only a light pruning is needed. Any growth that occurs after pruning will be the stems that will produce buds for next year's flowers. If you want these vines to spread quickly, only prune to remove dead or damaged growth. To keep vigorous growth under control, you’ll want to prune back a bit more. Try to avoid pruning any woody growth.
Group #2: Included in this group are early and mid-season large-flowering, double and semi-double clematis. These plants can be a little tricky because they flower on both old and new wood. The biggest flush with the largest flowers is in spring on old wood, followed by a smaller flush in fall, or even by a steady, small amount of flowers throughout the summer. When pruning, follow the vine down to a swelling leaf axle bud and prune right above it.
Not a very good example, but if you look at the large vine right at the place where its branching out, you can see the leaf axil buds just beginning to form.
Remove any dead wood, tidy the vine up a bit, and prune back to keep growth in check. If you have a big tangle of vines left from last year, try to untangle as many vines as you can after the first flush of flowers. If you can't untangle the vines, this is the time for a hard pruning, up to as much as 1/3 of each vine. If you do a hard pruning and your plant has double flowers, you may only get single flowers later this year. To keep a more natural look, stagger the length of the vines as you trim them back. Tie any new growth to supports to keep the plant open to air and sunlight. You’ll also want to remove any old leaf stalks remaining on the vines from last year. Plants in this group tend to get bare toward the bottom as they get older and do well with other plants around them, covering their bare stems. If they get too top heavy, they can be pruned back quite hard without damaging them. If you live in a very cold area, you’ll probably have to prune back farther due to damage by winter weather, or you may not have a choice at all if they die back to the ground.
Notice the flowers all the way to the ground on this beautifully pruned clematis.
Some suggest that Group 2 plants should be cut back hard every third year to avoid the tangled, old growth that can occur on the top of these plants.
If you’re feeling adventurous, you can also do a special “second-year pruning” on these clematises, and on Group 1 plants as well. This is another hard pruning, but this time it entails cutting back the vines to about three feet from the ground. Again, this causes more new stems to grow from the ground and stimulates the vines to branch out. This isn’t necessary, but it will improve the appearance and health of your clematis in subsequent years.
Group #3: Late large-flowering, late flowering species, and viticella clematises make up this group. They generally die back to the ground in winter in cold areas. If not, they respond well to hard pruning and can be cut back to about two feet tall. They usually get flowers on the last several feet of new growth and can be cut back even farther because they don’t bloom on old wood. Like the Group 2 vines, they will get bare stems toward the bottom as they age if they aren't cut back hard. Hard pruning sounds brutal, but it will reward you with lots of new growth and many flowers. As the new growth appears, tie it to supports to keep it looking its best. This is probably the easiest group to prune.
There are also clematises known as integrifolia or herbaceous clematises. These are non-vining perennials with a dense and somewhat sprawling habit. Although they can't attach themselves to a support, they can be tied to one or left to sprawl on the ground. These can be cut to the ground with your other perennials in late fall or early spring.
Another reason to prune is to control wilt. Clematis wilt occurs when the ends of the vine turn black and the vine, or even the entire plant, collapses. When this happens, cutting the plant all the way back to the ground will produce new growth. This is a radical pruning method but it will save your plant.
As you gain more experience with the clematises you have, you’ll be able to recognize the three pruning groups from their bloom time. Group 1 blooms in early spring, Group 2 blooms on old wood in the spring and new wood later in the year, and Group 3 blooms on new wood late in the year.
Now that you know how easy it is to prune them, your plants will be happier and prettier and will produce more flowers. Quite an impressive return on investment for only a few minutes a year!
Every clematis vine benefits from judicious pruning. But many people are so unsure about the proper time to prune their clematis that they avoid it altogether, and the vine becomes an unattractive, tangled mass of brittle, easily-damaged growth.
(Editor's Note: This article was originally published on March 24, 2010. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
Be reassured that incorrect pruning will not bring about the early demise of your beautiful bloomer. In fact, there are times--such as when you are training a newly-planted clematis, rejuvenating an old one, or removing stems affected by disease--that beg for a little tough love with the clippers. Even if you do prune a clematis too much or at the wrong time, the worst case scenario is that it will not bloom until the next year.
Most gardeners have heard that timing of clematis pruning depends on whether the vine is categorized as part of group 1, 2 or 3 (the groups are also sometimes labelled as A, B and C). So how do you know what kind you have? Many of the clematis sold at nurseries today have the group number displayed right on the plant tag. If you know the name of your clematis variety, you can look it up. FineGardening.com provides an useful list of some of the most popular clematis varieties and their pruning groups here.
If you are not sure which variety you have, observe its flower size and blooming habits. Does it bloom early in the season, producing large flowers on brown, woody growth? Then it’s probably in the Group 1 category. If it doesn’t begin blooming until June, and often produces a second crop of smaller flowers late in the season, it’s likely Group 2. And if it has smaller flowers which appear on green stems in summer or fall, it’s most likely Group 3.
Clematis Pruning Tips
• Avoid pruning your clematis late in the season if you live in an area with cold winters.
• You can deadhead early blooming varieties to encourage a second bloom, but you will miss the seed heads which you can enjoy right into winter.
• Always make your cuts just above the fat buds.
• Dispose of clematis clippings in the trash rather than your compost pile, and keep fallen leaves raked up to discourage fungal disease.
Group 1 clematis bloom the earliest, between April and June, depending on your zone. This group includes C. montana, C. alpina, C. macropetala and C. armandii. These clematis bloom on old growth--all their flower buds were produced in the last season. Prune these early bloomers very lightly in early spring, moving top down to the highest pair of buds, removing only dead or damaged stems. Any other pruning should be done immediately following blooming, so the vine will have plenty of growing time to produce new buds for the next season. Avoid cutting back the woody stems of any vine in Group 1.
Group 1 Clematis :
Group 2 clematis are large-flowered hybrids which produce a heavy display in June on old wood, then a second bloom (with smaller flowers) later in the summer on new growth. Hybrids ‘Miss Bateman’, ‘Nelly Moser’ and ‘General Sikorski’ are just a few in this category. Group 2 vines require more early spring pruning than Group 1, but since the majority of the bloom is on old wood, you don’t want to trim away too much. Starting at the top, prune back one stem at a time to a healthy bud. If the vine has become tangled and requires a hard cutting back, the best time to do this is after the first flush of bloom, so the vine still has time to put on growth before the end of the season. Some varieties bloom on old and new wood simultaneously, meaning that they are in bloom almost continuously. It’s always hard to trim away a plant that is blooming, but in the long run you will be rewarded with more flowers on a healthier plant.
Group 2 Clematis :
These summer or fall bloomers are smaller-flowered and bloom on new growth only, so you will want to prune them hard in early spring, removing all the old growth. C. terniflora (sweet autumn clematis) and hybrids ‘Ernest Markham’ and ‘Comtesse de Bouchard’ fall in this category. Group 3 clematis are the easiest to prune, because although you cut away more of the plant, there is little decision-making necessary. Just be sure you leave two sets of healthy buds on each stem, about 12 to 30 inches above the ground. These vines start their new growth close to where last year’s growth ended. Left unpruned, they will develop long, twiggy stems at the base. If your goal is to have the clematis bloom on a support far above the ground, you might actually want to encourage this.
Group 3 Clematis :
Training a Young Clematis
Anxious though you may be to see your newly planted clematis bloom for the first time, some patience is required, since these vines need a strong root system to support luxuriant growth. Prune a young clematis back to 18 to 24 inches in its first season, no matter which group it falls in. Doing so encourages branching and will improve the vine’s appearance and flower production in the future.
Rejuvenating an Old Clematis
If you have a clematis so overgrown and tangled that it is no longer blooming and you don’t even know where to start pruning, you can rejuvenate it by cutting it almost back to the ground in very early spring. Within a year’s time, you will once again be rewarded with bountiful blooms. After pruning, a clematis will put on growth quickly, so be sure to keep it watered and fertilized even when it's not blooming.
Title Photo: Clematis 'Jackmanii' by Joy
Other photos: Todd_Boland bootandall Shirley1md kniphofia DebinSC handhelpers tyke Bug_Girl kell victorgardener TomC_UK mystic dinu Evert
Whatever variety of Clematis you choose, pruning is a key part of successful growth and bountiful blooming. Many gardeners are confused by when to prune Clematis and how to do it, so we've put together this guide for you to follow on when and how to prune Clematis.
Do you know when your clematis breaks into bloom? If you do then you will be able to work out when the best time for pruning will be. Clematis are split into three pruning groups according to the flowering season. If you are unsure when your Clematis blooms, the best thing to do is wait until the first flowers appear, note the month and then you will be able to work out what group your clematis belongs to. Don’t just go ahead and hack the stems down thinking that it won’t matter, as this may well cause irreversible damage to the plant.
Flowers through late Spring and Summer and those which flower twice (once in early Spring and again late Summer). Varieties in this group include the large-flowered Nelly Moser, Niobe, Bees Jubilee, Aneta and Princess Charlotte.
Flowers late summer. Varieties in this group include Jackmanii, Minuet, Prince George and Viticella.
All newly planted Clematis with just one or two healthy base stems should be given a hard pruning the first spring after planting. For established Clematis, follow the Clematis pruning group's dates as follows:
This is the no pruning category (hooray). These varieties don’t need to be pruned regularly to provide you with an abundance of growth and blooms.
Pruning should take place at some point in February (late Winter - early Spring). If the variety flowers twice, then a second pruning should take place in early Summer (May - June) after the first flush of blooms.
Pruning should take place in February (late Winter - early Spring).
All newly planted Clematis can be pruned back to about 30cm above the ground, in the first spring following planting. This should encourage strong stem growth and a good base for the future growth of the plant. Ensure that this hard pruning takes place after the risk of frost has passed around March. For established Clematis plants follow the group pruning guide as follows:
When a plant has suffered the trauma of pruning, it is a good idea to give it a good feed to help recovery. A potassium-rich or rose fertiliser would be ideal.
Do you have a Clematis of which you are particularly proud? We’d love to see your photos, you can share them on our Facebook page or Twitter. Also if you have any great tips for growing or pruning?
Some members were concerned about the thorny subject of Clematis pruning…which, when and how. I promised that I’d write a blog in the gap between the open days…while I have nothing to do in the garden!! LOL . (Who am I kidding?)
I will tell you all about my first ever Open Days after the 11th. I’ll just say that yesterday went very, very well. :-)
Back to Clematis. I am not an expert but I have built up quite a collection of Clematis, flowering right through the year, so I can pass on what I’ve learned, anyway!
That’s a familiar one, isn’t it!
Clematis are divided into three groups for pruning purposes … if you buy a new one, the label will tell you that your new plant is in group 1, 2 or 3 … possibly using A, B or C instead of the numbers.
If you have older plants and no labels, it is easy to check the group if you know the name of your Clematis, on GOY , via the Clematis Society website, or of course in a book.
Group 1 Clematis
Evergreen winter and early spring flowering Clematis fall into group 1. So these will include the C. cirrhosas like ‘Freckles’, C. Armandii, the C. montanas like my favourite ‘Broughton Star’…
C. alpinas, like this one which is called C. alpina ‘Helsingborg’
And C. macropetalas like this pretty one called ‘Blue Lagoon’.
Group 1 Clematis do not have to be pruned – apart from cutting out dead or damaged shoots – unless they are outgrowing the space you have for them. This can happen with the more vigorous ones, especially the montana group. They will not object at all to being cut back after they have flowered….if you do it before, you’ll lose the flowers! It’s best to keep the cutting back to a trim, but they can be cut hard back if necessary.
Group 2 Clematis:
Clematis in this group do need a little pruning before the new growth starts in early spring. It is best to cut out any damaged shoots at the top of the previous year’s growth, and then look for healthy pairs of buds further down each stem. Try to create a framework as these buds will produce strong shoots and then the flowers. Don’t cut back hard! This group usually has large flowers, in mid-spring, and then often flower again in late summer. C. ‘Nelly Moser’ is a group 2 Clematis, too.
Group 3 Clematis:
These are the ones that flower later in the summer, like Clematis jackmanii superba:
the C. viticellas, like C. ‘Etoile Violette’
and C. tangutica, aswell as the C. texensis group.
These Clematis should be cut hard back to about 10" above the ground – above healthy pairs of buds on each stem in early spring as soon as you can spot the buds. They will also grow quickly from each bud and need tying in to a framework. They flower only once, but usually give a fantastic show of colour as they do!
Please don’t forget that your Clematis is a greedy feeder – it needs feeding as you plant it, after you’ve pruned it, and during its growing season as well. I use blood, fish and bone around the root area in early spring, then a liquid feed for the rest of the time.
I do hope that this has de-mystified this subject a bit for those who were anxious about pruning their Clematis.