It’s no wonder Clematis are often called the “Queen of all Vines”—with their dazzling blooms, they truly are the stars of any sunny perennial garden!
While these gorgeous climbers can sometimes be a bit fussy to grow in Alberta, don’t let that discourage you.
In this blog, I’ll walk you through some helpful tips for caring for Clematis and offer simple advice on how to prune them, so you can enjoy their spectacular flowers year after year.
How to Care for Clematis
Clematis have 5 simple needs:
1. Clematis Need a Sunny Place to Grow
Clematis is a sun lover, requiring a minimum 6 hours or more to thrive. Clematis enjoys a break from the sun in the later afternoon to give it a respite from the heat and a little less intense sun at that time of day helps reduce flower fade on the older blossoms.
Be on the lookout for things that will compromise sunlight exposure to your Clematis. A neighbour’s house or garage next door, house eves, trees, fences, pillars, and posts can all block sunlight.
2. Clematis Like to Grow in Moist Soil
Clematis require a rich soil base that holds moisture but drains well.
Soggy soil can lead to death of a Clematis because its roots tend rot if they are too wet for too long.
To prevent overwatering, always check Clematis before hydrating the soil. An easy way to do this is to stick the entire length of your index finger into the soil and if you find that the soil is dry at the tip of your finger, or at the first knuckle, it’s time to water.
Monitor Clematis closely well during dry spells and water deeply.
3. Clematis Like to Have Cool Roots
Clematis like to grow in a spot that keeps their feet cool. As a matter of fact, once the soil temperature reaches 25 C (77 F), the roots will stop growing.
How do you accomplish that when they like to have their heads and stems sunny? You will have to create some shade for the base of the plant.
How to Create Shade for the Base of a Clematis plant:
- Use Mulch to Shade Plant Roots – mulch is a protective layer spread over the surface of soil. Mulch can cool soil down by preventing the soil from beating down on the soil.
- Place a layer a 7-9 cm (3-4 inch) layer of organic mulch like leaf and bark chips around the plant base to keep it shady. It’s important to keep the mulch away from the plant stem so it doesn’t get wet and infected.
- Plant a Shrub or Perennial near the Base of the Clematis – low growing shrubs, like a Spirea, or a robust perennial, like a tall Salvia or fall flowering Sedum will provide shade for the base of a Clematis vine.
- A Garden Ornament can Shade Clematis Roots – use garden decor such as a bird bath or bird feeder to shelter Clematis roots from too much sunshine.
Related: What is Mulch? Making Gardening Magic with Mulch
4. Vining Clematis Need Something to Climb
Being a vine, some Clematis can grow up to 20′ (6 m) long. Clematis have built-in long stems attached to their leaves, called petioles that twist around support structures.
Clematis climb support structures by wrapping their long petioles like arms around structures as they climb. Because the petioles are 4-6″ (10-15 cm) long, you need to watch that what you put in place is narrow enough for them to grasp onto.
Fences with wide boards and house siding, smooth or rough, will not work for Clematis, they will need some finer mesh or galvanized wire, like chicken wire to attach to.
Other supports that Clematis easily climb are trellises, obelisks, and arbors with narrow structures.
5. Clematis Need to be Fertilized Regularly
Fertilize Clematis regularly from June-August because they are actively growing. This is a different from other perennials because most perennials don’t need much fertilizer.
Feed Clematis as they emerge in spring with a slow release fertilizer with an formulation of 10-10-10 and during the growing season, apply a lower nitrogen formulation like 5-10-5 or15-30-15 to encourage bud and flower formation every 4-6 weeks, until the Clematis plant is in full bud.
Stop fertilizing when the Clematis is in full bud because too much fertilizer can cause the Clematis to lose its buds to make way for leafy foliage growth.
About Pruning Clematis
Why Prune Clematis?
A pruned clematis is a healthy Clematis.
Trimming Clematis controls the growth pattern and improves overall Clematis performance by:
- Improving air circulation throughout the vine
- Providing better light exposure all over the plant
- Stimulates fresh growth
- Boost flowering
When to Prune Clematis
Clematis are broken up into 3 different pruning classes and the label included with each Clematis plant should indicate which class they are.
The pruning groups are divided as A,B, & C – or 1,2, & 3. Group A would be the same as Group 1, Group B the same as Group 2, and Group C the same as Group 3.
Let’s look at each Clematis Pruning Group individually:
When to Prune Clematis Pruning Group A
This group of Clematis blooms on old wood from the previous year’s growth. This group is typically from warmer horticultural growing zones 6 & 7, so we won’t see these in the Alberta area.
The old, dead wood is cut back from this group in spring or summer after they have budded.
Alpine Clematis and evergreen Clematis armandii belong to this group.
When to Prune Clematis Pruning Group B
Clematis Group B is a large flowering type that is usually rated for Zone 4 growing climates. Most Clematis that grow in Canada are in this group.
This is a group of plants that flower heavily in the spring and then it continue to bloom all through the summer, but not as profusely as it did in the spring.
Clematis group B is divided into two subgroups: B1 & B2.
- Clematis Group B1: Initially flowers on older stems in spring and reblooms on new growth in the late summer.
- Clematis Group B2: The blossoms occur on older stems and new growth simultaneously.
For pruning both subgroups, there are 2 options:
- Lightly prune a few stems in the spring to encourage strong buds & to promote branching & blossoms on new growth while letting other old stems grow to produce the spring bloom
- OR, you could prune the entire plant back every two years and miss the spring flush
Varieties that belong to this group include Nelly Moser, Henryii, Multi Blue, Vancouver, and The President.
When to Prune Clematis Group C
Clematis Group C is a later bloomer and only flowers on new growth. Once they get going, they will bloom from July until frost in the autumn.
This group comprises Clematis that are usually horticultural Zones 5 and 6.
Prune back this group hard in early spring by counting up the stem to four leaf nodes from the ground (this will probably come to 30 cm or 12″ from the soil line).
This pruning will encourage branching, thicker growth, and more flowering.
Jackmanii, Jackmanii Superba, Polish Spirit, Prince Charles, and Comtesse de Bouchaud are varieties in pruning group C.
Pruning Clematis Step by Step
Trimming Clematis is quite simple; all you need is a few simple tools and you will be on your way!
The tools you will need to trim a Clematis include:
- Hand Clippers – freshly washed in warm, soapy water to prevent the transmission of bacteria or any other damaging soil borne infection.
- Fasteners to attach Clematis to the Support Structure – hook & loop tape or another gentle tie will work well for this
How to Prune a Clematis
- Determine where the Clematis needs to be trimmed. Some guidelines recommend trimming Clematis at12″ (30 cm) above the ground, while other Clematis types have different requirements. Once you know where you need to trim, get your clippers out.
- Trim the Clematis stem by stem so you cut it back in the right place.
- Cut the Clematis just above the leaf nodes as seen in the photo. Leaf nodes are the spot on the stem where the leaves come out of the stem. Clematis have two leaves that come out of the stem opposite one another.
- Once you have finished pruning, collect all the stems and leaves and remove them from the Clematis growing area. Keeping the growing space clean from decomposing Clematis material helps reduce the spread of disease.
- Wash your clippers after you are done so they are clean and ready for their next task.
To Sum up the Care & Pruning of Clematis
Clematis are truly special flowers, and setting them up for success starts with choosing the right spot in your garden.
After planting, there are just a few basics to keep in mind. Make sure your Clematis isn’t planted too shallow, provide good drainage, and avoid letting the roots stay too wet—these simple steps make a big difference in keeping your plant healthy and happy.
While the idea of three different pruning groups might sound confusing at first, the good news for Alberta gardeners is that most Clematis here fall into group 2, which takes the guesswork out of pruning.
Once your Clematis is established, you can look forward to years of vibrant blooms and lasting beauty in your garden.
More to Explore
- 5+ Clematis Varieties That Work Well in Alberta
- A Step by Step Guide on How to Plant Clematis
- 10+ Amazing Annual and Perennial Flowers to Grow in Full Sun
- Understanding Perennial Seasons of Bloom [+ Perennial Flowering Reference Chart]
- 6+ Front Door Planter Ideas to Make Your Entrance Shine
© Sharon Wallish Murphy, Gardening with Sharon
