If you’re wondering why your clematis isn’t blooming as much as you’d like, the key could be in how and when you prune it.
I know how it is—standing in front of a mess of clematis vines, wondering where to start can be pretty overwhelming. A lot of the confusion comes from the fact that different clematis varieties have different pruning needs. Some need to be cut down to the ground every year, while others just need a little trim to stay in shape.
So, how do you figure out which is which?
The key is knowing which pruning group it belongs to.
Back in the 1950s, garden experts divided clematis into three groups Group 1, Group 2, Group 3 based on when they bloom, which determines how and when you should prune them. If you have the plant tag, that’ll tell you the group. If not, you can always look up the variety name if you know it. And if you’re not sure about any of that, just watch your plant for a year and note when it flowers.
Once you know when your clematis blooms, you can easily figure out the group it’s in and prune accordingly. Whether it’s an early spring bloomer, a repeat bloomers, or a late summer star, getting the pruning timing right will make sure you’re not missing out on any of those gorgeous flowers.
I know it might still sound complicated, so here’s my simple, straightforward guide to figuring out your clematis’ pruning group and when to prune it, so you can keep those blooms coming year after year.
Why prune clematis anyway?
So, why even bother pruning your clematis? If you just let them do their thing, they can turn into this wild, overgrown mess of old stems that hardly produce any flowers. And for those super vigorous varieties, they’ll end up throwing most of their blooms way up high, where you can’t really enjoy them.
Plus, they can get so heavy that they might even pull down their support or collapse under their own weight. Giving them a good prune helps encourage fresh growth, which means more flowers—and at a height where you can actually see and enjoy them. It also keeps the plant from getting too top-heavy.
On top of that, regular pruning keeps clematis healthy. . Clematis can sometimes get hit with this nasty thing called clematis wilt, where whole shoots or even vines suddenly turn brown and die off, usually in early summer. If you catch it early and prune back the affected parts to where the plant is still healthy, or even cut the whole thing back to the ground if you have to, you can stop the disease from spreading and encourage new growth. Plus, pruning helps thin out that dense tangle of stems, letting in more air and light, which keeps things drier and less likely to get diseases like wilt.
Pruning Group 1 Clematis: Early Spring Blooming
Group 1 clematis are like the early risers of your garden, putting on a stunning show of blooms in the spring. These vines flower on old wood, which means they rely on the stems that grew last year. The tricky part? Prune too early, and you might accidentally snip away the buds that would become this year’s flowers.
To identify if your clematis is in Group 1, just keep an eye on when it blooms. If you see flowers in the spring, that’s a pretty solid sign you’ve got a Group 1 variety. Popular types in this group include Clematis montana, Clematis alpina, and Clematis armandii. Each of these has its own special look, but they all share the habit of using last year’s growth to produce their spring display.
Timing is Crucial: The best time to prune your Group 1 clematis is right after they’ve finished blooming in the spring (around May or June) and no later than July. If you prune before they bloom, you’ll be cutting off the flower buds and missing out on the show.
Shape and Support: For more vigorous varieties like Clematis armandii, you might need to trim them back more heavily to keep them in check and maintain a shape that works well in your space. If they start getting out of hand, you can even cut them back close to the ground.
Light Trimming: For slower-growing varieties like Clematis alpina, a light trim to tidy up any wayward stems is usually all that’s needed. Remember, since these clematis bloom on old wood, cutting too low or too early could cost you some flowers!
Clematis belong to cutting group 1
Alpine clematis (Clematis alpina)
- ‘Jacqueline du Pre’
- ‘Pamela Jackman’
- ‘Pink Flamingo’
- ‘Ruby’
Mountain clematis (Clematis montana)
- ‘Elizabeth’
- ‘Tetrarose’
Clematis macropetala ‘Rubra Marginata’
Group 2: Repeat Bloomers
If your clematis flowers seem to have a mind of their own, bursting into full bloom not once, but twice a year, you’re likely experiencing the joy of Group 2 clematis.
These vines are the mid-season stars, kicking off with blooms on old wood in late spring to early summer, and then surprising you with a second round of flowers on new growth later in the season, often stretching into early fall.
Group 2 clematis needs a bit more careful pruning than other types—get it wrong, and you might miss out on a good chunk of their flowering show.
Timing Is Everything: Start by pruning your Group 2 clematis in late winter or early spring, around February to March, just as the buds start to swell. This timing is crucial for encouraging a robust spring bloom while also setting the stage for the second flowering later in the year.
Light Touch in Spring: As you get started, remember to prune lightly. Remove weak or dead stems but ensure you retain enough of last year’s growth to enjoy those early blooms.
Second Prune After First Bloom: After the first flush of flowers has faded, typically in June or July, it’s time to prune again. Cut back the stems that held the flowers to encourage new growth, which will produce the second flush of blooms. This keeps the plant looking fresh and sets it up for the next round of flowers.
Alternate Year Pruning: Some gardeners prefer to cut these vines back by half every other year, allowing them to grow more freely in the alternating years.
Drastic Pruning: Alternatively, every few years, you might prune the whole plant sharply just before new growth begins. Although this means sacrificing the initial blooms one season, it rejuvenates the vine and maintains its health and shape.
These clematis belong to cutting group 2
My favorite varieties of Clematis hybrids
- ‘Alabaster’
- ‘Dr. Ruppel’
- ‘Duchess of Edinburgh’
- ‘Fireworks’
- ‘HF Young’
- ‘Catherine’
- ‘King’s Child’
- ‘Azure Star’
- ‘Piilu’
- ‘Pink Fantasy’
Group 3: Summer or Fall Bloomers
Clematis vines from Group 3 are like nature’s fireworks, saving their stunning show for late summer and fall. Unlike their counterparts, these clematis bloom on new growth. If you skip the pruning, you’ll end up with flowers way up high and just a bunch of bare stems and leaves at eye level.
Pruning Group 3 clematis is as easy as it gets.
Time It Right: Late winter or Early spring is the best time to prune Group 3 clematis. As soon as the danger of frost has passed and new buds begin to swell, it’s time to get to work. This timing encourages new growth that will carry flowers later in the season.
Cut Back Hard: Don’t be shy! Cut all stems back to about 12 to 18 inches above the ground. Aim to make your cuts just above a healthy bud. This might sound drastic, but remember, for these clematis, blooming happens on new stems.
Mind the Buds: As you prune, ensure that you’re cutting above strong buds. These are the starting points for new branches that will turn into flower carriers.
Promote Air Circulation: Remove any tangled or damaged stems. This cleanup encourages air flow around the plant, reducing the risk of diseases and helping the plant to focus energy on new growth.
Annual Ritual: Make this severe pruning an annual habit. Unlike other clematis groups, Group 3 handles this approach very well, rewarding you with a buffer of blooms each year.
These clematis belong to cutting group 3
These include numerous clematis hybrids and wild species.
Clematis hybrids
- ‘ Jackmannii’
Clematis sylvestris
- ‘ Silly’
- ‘ Leunora’
Clematis sylvestris
Clematis vulgaris
Clematis texensis
How to Prune an Unknown Variety of Clematis
Pruning clematis can be a bit of a headache, especially if you don’t know which variety you have. But don’t let that stop you! Pruning is crucial to keep your clematis healthy and blooming where you can actually see the flowers, not just at the top of the plant.
Here’s a straightforward approach if you’re unsure about the variety:
- Timing and Observation: The golden rule is, “If it flowers before June, don’t prune.” This covers early bloomers like Montanas, alpinas, and winter-flowering clematis. Pruning these early in the year can disrupt their flowering cycle, so leave them be.
- What to Do If You’re Unsure: If you don’t know what type you have and it’s already February or March, it’s time to prune. Most likely, your clematis will bloom after June, meaning it falls into either Group 2 or Group 3.
- When in Doubt, Treat It as Group 2: If you’re not sure which group your clematis belongs to, treat it as a Group 2. Prune it down to a framework, and you won’t go far wrong.
