Clematis: How to Grow Clematis
You take one look at clematis in bloom and you’ll know exactly why it’s also known as the Queen of Climbers. The flowering vine comes in all sorts of colors – from the whitest whites and pale pinks, to deep purples and vibrant crimsons. The hardy vine comes in quite a range of sizes and shapes too. Some are evergreen, while others may be deciduous or perennial. The clematis make up a flowering plant family with the aesthetics that many people love.
As any good horticulturist knows, it’s always better to have more knowledge about the plants you want to take care of. So while it isn’t too difficult to care for the hardy clematis, you’d probably still want to get to know them more!
Clematises are made up of about 300 species of plants within the buttercup family. Its name in Ancient Greek literally means “a climbing plant”, though there are some clematis species that are more like shrubs than climbing vines. Some may have small and delicate flowers, while others boast of flowers the size of plates.
Clematis plants all share similar characteristics though, hence why they’re grouped in the same genus. Otherwise, it’d be very difficult to tell them apart from other flowering vines! You’ll learn more about how they look like and more in the next sections.
Facts About Clematis
Clematis vines originally came from China. They were brought to Japan in the 17th century, and reached the European gardens in the 18th century. By the 19th century, more than 200 clematis species have already been identified. More than 100 species are of Chinese and Japanese origin, considered by many to be some of the finest species of the Clematis family.
Many clematis plants were introduced to Europe, but only the hardiest vines really flourished. The C. cirrhosa, for example, was first introduced to Europe, but its cultivars known as Freckles, Jingle Bells, and Ourika Valley became some of the most famous flowering clematis to withstand Europe’s harsh winters.
Breeding free-flowering, colorful, hardy, and evergreen clematis plantsbecame the hobby of many horticulturists throughout the 18th and the 19th century. However, years of low-quality inbreeding resulted to a wilting sickness in the 20th century.
As tough as they could be with the cold, clematis may be difficult to grow because of their tender and fragile stems. They’re picky plants when it comes to setting their roots too. Many of the hardier clematis species can survive winters though. Some will even start blooming during winter to late autumn, and some will even flower twice during the flowering season!
Ideally, clematis are grown in a sunny spot where they can receive at least 6 hours of sun a day, and this is why most clematis are planted during the spring. There are some cultivars that won’t have a problem blooming in partial shade, though they may not have as many blooms as those that get their full-day sun.
It’s quite easy to know when you’re looking at a clematis plant. While they come in many different shapes, sizes, and colors, clematis are known to share some similar traits that make it easy for even newbie gardeners and hobbyists to identify them.
When mature, the average height of clematis vines range from 6 to 12 feet. Some cultivars grow taller though.
For example, the Jackman cultivars can grow up to 20 feet in height. When supported or allowed to grow along a tree, the taller clematis anemone can grow up to 24 to 40 feet in height. The fragrant sweet autumn clematis usually mature at 15 feet, but they can still grow up to 30 feet in height.
There are smaller clematis vines too, but even they can still reach up to 5 to 6 feet. Betty Corning is a popular clematis cultivar that averages about 5 feet. Bourbon is another cultivar that grows about 5 feet tall. The Bijou, Elodi, Emerald Dream, and Filigree cultivars are known to just grow up to 2 feet tall.
To know if you’re actually looking at clematis, take a close look at the leaves along the stems. Around the stems, clematis leaves will grow in pairs. If they’re alternating, it’s definitely not a clematis cultivar or variety. Other vines have leaf pairs along the stems too, so this is just to rule out any other flowering vines that may look like but aren’t clematis. The stems are also divided into stalks and leaflets, helping the plant climb and cling onto trellises and other supporting structures.
Fun fact: Caterpillars generally like clematis leaves!
The flowers of the clematis plants vary in shape, size, and color. Most flowers feature 6 to 8 petals. Some cultivars may have double blossoms or bell-like flowers. Large-flowered clematis are usually very colorful but lack scent. They are also more prone to wilt. Small-flowered clematis usually carry a scent, and they’re less prone to wilting and other fungal plan infections.
Color and Size
There is a wide variety of clematis flower colors and sizes. Here are some of the most popular:
- The President – Purple-blue flowers, up to 7 inches in diameter
- Henryi – Pure white petals with brown to violet centers, 6 to 8 inches in diameter
- Claire de Lune – White to off-white, wavy blooms with lilac along the edges and deep purple anthers, 5 to 8 inches in diameter
- Bill MacKenzie – Down-facing yellow blooms, 2 to 3 inches in diameter
- Rebecca – Red velvet with creamy yellow centers, 5 to 7 inches in diameter
- Diamond Ball – White-blue and round double blooms, 4 to 5 inches in diameter
- Evergreen Avalanche – White blooms, up to 3 inches in diameter (some of the biggest flowers of the evergreen varieties)
- Duchess of Albany – Bell-shaped, deep pink flowers with light pink edges, 2 to 3 inches in diameter
The evergreen clematis are usually small-flowered and are beautiful all-year-round, but many other clematis plants bloom at different seasons.
In the middle of the spring season, the Atragene group of clematis bloom. They’re some of the hardiest and easiest to care for clematis varieties. Blue Dancer, Frances Rivis, Frankie, Markham’s Pink, and Pamela Jackman are all part of the Atragene group. These have nodding, down-facing, and lantern-shaped flowers.
Clematis that bloom in late spring or early summer do so on the previous year’s blooms. They will often bloom on new wood late in the summer or early in the fall. Most of these repeat bloomers have large flowers that reach up to 8 to 10 inches, and the smaller ones can still be at least 5 inches in diameter.
Some early repeat bloomers include Bees’ Jubilee, Duchess of Edinburgh, Fireworks, Henryi, and Rosemoor. Their foliage, however beautiful, is prone to clematis wilt. Some late repeat bloomers include Blue Angel, Fond Memories, Honora, Jackmanii, Romantika, and Ville de Lyon. Their foliage is prone to the powdery mildew infection.
Summer or Fall Bloomers
Herbaceous clematis are known to bloom over long seasons, mostly from early summer to early fall. After blooming the first time, they’ll bloom again within a month and a half. Some areas even experience a third wave of blooms.
As part of the herbaceous group, they aren’t climbers like other clematis varieties. Their small, mostly blue flowers aren’t usually affected by clematis wilt. Other varieties may be white or light pink in color.
How to Grow Clematis
Since there are just so many clematis varieties, knowing just what you’re working with can help you better take care of the plant! In this section, you’ll find a few tips and tricks to help you out.
You don’t need to find the perfect soil for clematis to grow on. However, the perfect foundation can help your clematis bloom for many years after planting.
Loom soil is perfect for clematis because it provides the perfect amount of moisture and nutrients to grow. It needs to be loose for 2-feet deep for enough drainage and aeration. Amending the soil is a great idea, especially for less than ideal soil. If the soil is slightly acidic, consider a limestone treatment.
Clematis need nutrients, especially during its early years. Before planting or transplanting clematis, you can incorporate some organic matter or compost into the loosened soil. Every spring, you can add an inch of compost on top of the soil bed.
Clematises love the sun. They need at least 6 hours of sunlight every day for them to bloom to their full potential, so correct placement is very important. Varieties like the Andromeda, Carnaby, Mercury, and some others can live in partial shade. Clematises are planted to grow around shrubs and trees, so they can definitely live in partial shade, but they may not grow as colorful as those planted in a sunny spot.
If you’re planting herbaceous clematis though, you’re definitely going to need a location that offers full sun. If you’re planting some spring-flowering or winter-flowering evergreen clematis, you might need to offer them some shelter as they aren’t as hardy as those that bloom in summer and fall.
Fading colors in clematis flowers may be caused by too much or too little sunlight. If not given enough sunlight, the plant won’t be able to photosynthesize effectively. If given too much, their colors may fade (and this is mostly true for most blue and violet variants).
Both the stems and foliage benefit more from locations that get plenty of eastern sunlight, but the soil itself should be cool and shaded. During the spring, 2 inches of fresh mulch should be applied around the base of the plant. If you’re planting in a hotter climate, consider planting them on the northern walls.
Temperature & Humidity
To grow and flourish, clematis require a night temperature of about 7.5°C. This is why most are planted in countries with colder climates. It’s not impossible to grow and care for clematis in temperate climates though. However, you may find that the clematis grown in areas with hotter climates tend to be less vibrant than those planted in areas with colder climates. Red clematis flowers seem to be an exception as they are sometimes more vibrant in hotter temperatures. The humidity in the summer or in warmer climates can help minimize fungal infections.
The soil should be kept moist with plenty of water, but not so much that the soil is wet. A good indication that the plant needs watering is if the topmost inch of soil is starting to dry. If it gets too dry, overall growth is stunted and you’d see the leaves start to wilt, turn to yellow, then brown, and then fall off. If there is too much water, even the new leaves will fall off. Cracked soil means it’s too dry, and mushy soil means it’s too wet.
When it’s newly planted, water your clematis twice to thrice a week. Proper drainage is important for any plant, so check for this in between watering. After a few weeks, how often you water will depend on a few factors. An established clematis plant would only need an inch of water every week. It may depend on the weather, or how fast or how slow the soil is draining. Watch out for summer droughts and use rain gauge after a rain to see if your plant still needs watering.
Fertilizers may not be necessary if you have great, nutrient-rich soil, as great soil may sometimes be sufficient for the heavy-feeding clematis. Some clematis like the Clematis Montana, Armandii, Cirrhosa (Jingle Bells and Freckles), and Copper Beauty are fast-growers while some are not. Fast-growing varieties are easier to care for, but only if they receive enough sun, water, and nutrients. Most varieties are usually slow growers during their first year, but grow vigorously by their third season.
When it comes to clematis, there are three pruning groups. They are divided based on the season in which they bloom. However, you can always prune a dead or a damaged stem whenever you see one. You also need to remember that the best year to prune clematis would be on its second year of planting, and after flowering.
- Group 1 – Flowers bloom early in spring on shoots from last year’s growth. Remove the faded flowers. Plants may be cut back to 6 inches from the base for renovation, but you won’t be able to do this again for 3 years.
- Group 2 – Large-flowered clematis cultivars flower from May to June on last year’s bloom. Repeat bloomers will flower on new wood. As soon as it finishes flowering, cut the flowers back to a large growth bud. You can also choose to just leave them be, but remove the dead shoots still.
- Group 3 – Flowers bloom on the current year’s growth from midsummer to late summer. Prune hard in February to the lowest bud pairs. If left alone, Group 3 clematis will continue growing from where it stopped the last season.
Take cuttings from a healthy clematis plant early in the summer. Take those that are still quite greenish and have just started to turn brown. It may take a month or two for the cutting to take root. Meanwhile, keep them in a bright, humid spot without giving much direct light.
Clematises will struggle when they’re uprooted for replanting. It stresses them out, and most will take a year or so to recover from the uprooting. If you’re moving into a new home, or the clematis isn’t really thriving in its current location, you may of course consider transplanting.
The best time to transplant a clematis plant would be during the spring. If a spring transplant isn’t possible, just make sure that you don’t do it on a hot day. If transplanting during the fall, make sure to do it early and never later than October 1. You need to give your plants enough time to take root and settle in before the frost comes.
- Dig a hole for the clematis to be transplanted. Make sure it has more than enough space for the clematis’ roots so you can preserve them. Mix the dirt you’ve removed with some organic material to make your clematis’ new home nutrient-rich. If you’re worried about acidity, give the soil some limestone treatment.
- Dig up your clematis, and trim the roots about a foot or two from the ground. Put it in a wheelbarrow filled halfway with water. It’d be best if you can transport your clematis in this water. You can consider root stimulators to lessen the stress on the roots as well.
- Let the clematis sit on the water and root stimulator for a while before transplanting it back to soil. Plant it deeper in as it’ll be healthier for the crown and the lowest shoots to be covered in loose soil.
Clematis Pests and Diseases
Unlike other plants and trees, there aren’t pests that are specific to the clematis. But as clematis are usually planted alongside roses, the same pests that damage roses may damage clematis too. Aphids, whiteflies, earwigs, red spider mites, and slugs and snails can destroy clematis plants. Birds, mice, and rabbits can sometimes be culprits too.
One of the reasons why clematis is popular with even beginners to gardening is the fact that very few diseases can seriously damage the plant. Many gardeners are familiar with clematis wilt though.
Clematis wilt usually affects the large-flower clematis hybrids. The disease is caused by a fungus called Ascochyta clematidina.
It’s fairly easy to spot clematis wilt as it comes with the following symptoms: sudden stem collapse, foliage wither, and sometimes blackened stems and leaves. If a clematis plant is infected with this disease, you’re going to see the first symptoms during early summer because of the high humidity and damp weathers that the fungus finds favorable.
Clematises are some of the most attractive climbing plants with some of the widest variety of flower sizes, shapes, and colors. While they aren’t exactly easy to take care of, it isn’t all too difficult too. They do quite well in colder climates, and they’ll require minimal care once they’ve established and taken root. You can even plant them alongside other shrubs and flowering plants to complement their foliage as they can bloom when other plants cannot!
Frequently Asked Questions
When does clematis bloom?
It actually depends on the type of clematis! There are evergreen clematises that can bloom in the winter, and there are many clematis groups that bloom anywhere from early spring to early fall. For example, Atragene clematises bloom in mid-spring season, Montana clematises bloom late in the spring, some herbaceous clematises bloom early in the summer, and the Orientalis and Viticella clematises bloom early in the fall.
How fast does clematis grow?
Once they start growing, clematises grow quite fast. The growth rate depends on the variant or cultivar though. There are variants that can grow vines up to 30 feet in length, and there are shrub variants that only grow 2 to 5 feet in height. They grow quite slow during their first year as they’re still starting to establish their roots. Most clematises will start their rapid growth after their third season. So, don’t worry if you aren’t really seeing much progress during their first year. As long as you give them good soil, plenty of light, and enough moisture, they’ll reward you with blooms and vines in the seasons to come.
When’s the best time to prune clematis?
There are three pruning groups for the clematis, and the best time to prune clematises depend on which group it belongs to. For Group 1, the best time would be after flowering, and they’ll only require the pruning of faded flowers and dead stems. For Group 2, the best time would be after the repeat bloomers have flowered on new wood. For Group 3, pruning is best done during February, and it’ll require pruning to the lowest pair of buds. For all clematises though, you can always prune or cut a dead or damaged stem whenever you see one. It’s also best that you don’t prune a clematis on its first year of planting, as you want its energy and nutrients to focus on the roots instead of the stems.