Crematis care guide

How to grow clematis: clematis care guide from Fedor Fironov

Clematis are beautiful, and growing clematis in your garden can be a great pleasure and joy. The exceptional variety of shapes, colors and sizes of flowers, their brightness, unpretentiousness, ability to grow quickly and duration of flowering of many varieties make clematis a wonderful object of collection and a real decoration of the garden. Anyway, for me clematis are one of the main hobbies among ornamental plants.

I have been growing them for many years, and now my collection has more than 70 varieties. In this article, I will tell you how to care for clematis, how to plant them, how to properly feed and pruning.


Species and varieties of clematis

In total there are about 300 species of the genus Clematis, but in practice very few species and hybrid forms are grown in gardens in the United States, Great Britain and Canada. Most large-flowered clematis are hybrid forms that have been derived from crosses between clematis of different species and cultivars.

Of the small-flowered clematis, clematis terniflora, which is known in the United States as Sweet autumn clematis, as well as Сlematis montana and Clematis armandii have become the most popular. All of them are quite different and are grown in different ways.
In this article, however, I will talk mainly about planting and caring for large-flowered clematis.

Classification of large-flowered clematis

The classification of large-flowered clematis used to be very complicated and was based on the origin of the variety. However, in many varieties the origin is very difficult to determine, or they come from several species at once, i.e. they are hybrids. Therefore, a very simple classification of large-flowered clematis is now used: they are divided into two groups – early-flowering large-flowered clematis and late-flowering large-flowered clematis

Early flowering large-flowered clematis usually bloom for the first time around May and June, and again in August, September and even October. They bloom first on the previous year’s shoots and re-bloom on the current year’s shoots. Such clematis are cut long and belong to pruning group 2.

Late-flowering large-flowered clematis bloom on the current year’s shoots, so they bloom much later, usually in July, and bloom once. These clematis are cut short and are in pruning group 3.


Which clematis should I choose?

If you live in a region with cold winters and you do not have the time and desire to properly prune and cover clematis for the winter, you should choose clematis of the 3 pruning groups. Among them there are quite a few attractive varieties such as ‘Comtesse de Buchaud’, ‘Crimson King’, ‘Diana’ and others.

If you are in a region with warm winters and long summers, and you are ready to take care of clematis seriously, you can afford, including planting, early flowering large-flowered clematis. The vast majority of them have many varieties with terry and semi terry flowers. And, as a rule, the terry and semi terry flowers of clematis appear only at first flowering.

So you are very lucky if you are in a region where these clematis can keep last year’s shoots. You will see fantastic flowers of incredible beauty and you will be proud of your garden.

When to plant clematis?

It is best to plant clematis in the fall when the soil is cooler. In cooler soil, the root system of the clematis develops actively, while the cool air prevents the above-ground part of the plant from developing actively. This is exactly what is needed to prepare well for a long winter.

You can also plant clematis in early spring, when they have not yet touched growth. The worst option for planting is to plant clematis in the summer, because it is quite easy to damage the plants in the summer. In addition, in summer clematis actively build up the above-ground part, and if you traumatize their roots, they can suffer.

Transplanting clematis in summer

In summer, you can transplant clematis in a coma of earth. If you bought your clematis in the summer, do a transplant rather than a transplant. This will allow it to survive the planting much better and start building up roots and green mass more quickly.

How fast do clematis grow?

Clematis is characterized by a gradual growth of the root system and shoots. Some time after planting, the clematis will begin to build up its root system. At this time, its above-ground part will hardly grow at all. Don’t worry, it’s just building up a root system that will then allow it to feed a large mass of leaves and flowers.

After a while, it will quickly sprout up. Long shoots will appear on top and perhaps it will flower. Then again will come the stage of building up the root system, when there will be almost no growth of green mass. An adult large-flowered clematis can form shoots up to 5 meters long during the season, but most varieties have a maximum height of 1.5 to 4 meters

Be patient, look after your clematis and in a few years it will grow a large mass of shoots every year with beautiful leaves and absolutely gorgeous flowers.

How to plant clematis


Where to plant clematis

Choosing a clematis plot depends a lot on what state you are in and what kind of clematis you plan to plant. If you are in Michigan or another state with cold winters and moderately warm summers, you should choose open areas that are protected from the wind. If you are in Florida, Texas or another state with hot summers and virtually no winters, you will want to find a spot where the clematis will be slightly protected from the scorching midday rays.

What is the preferred soil for clematis?

All clematis grow well in loose, light, cultivated soils with a high humus content. Heavy clay soils, waterlogged soil, too acidic soil are not suitable for clematis. The optimal acidity of the soil should be close to neutral. Some species and varieties of clematis prefer slightly acidic soil, some – slightly alkaline.

However, if you are in a region with a long winter or rainy fall, a slightly alkaline soil is preferable. This is because soil fungi that can cause clematis fork are less likely to develop in slightly alkaline soil. Clematis fork is the most dangerous disease and it can kill your clematis in a matter of days.

Therefore, it is quite important to provide it with conditions for good growth and also provide conditions that will inhibit the growth of pathogenic soil fungi.

Is it necessary to prepare a planting hole for clematis?

Yes, it is necessary. A clematis planting pit should be no smaller than one and a half feet by one and a half feet by one and a half feet. For the first 2 or 3 years, the large-flowered clematis will only develop a root system within the pit, so this pit should have everything it needs to grow well.

The pit is filled with a mixture of soil that you extracted from it, with humus and mineral fertilizers, in particular, with superphosphate and potassium sulfate. Superphosphate leaches out quite slowly, so it will be enough for a long time. Potassium sulphate unfortunately leaches out of the soil quite quickly, but adding about 20g of superphosphate and 20g of potassium sulphate to the pit is a good idea.

Prolonged fertilizers

Many gardeners from the United States, Canada and the United Kingdom use a prolonged fertilizer such as Osmocote to fill the planting hole for clematis. This is a good option. Such fertilizers provide long-term effective nutrition, but they are quite expensive. If you are still willing to make that investment, choose Osmocote with a low nitrogen content and high phosphorus and potassium content.

Warning! Do not make drainage!

You should never put drainage at the bottom of the pit, especially if you have dense soil. If you put drainage at the bottom of the hole and fill it with looser soil than the surrounding soil, you will end up with a bowl that will collect water from all around. Therefore, in a rainy summer, the roots of your clematis can rot. This is very dangerous for the plant. Fill the hole only with the soil that you extracted from it. If the soil is very dense, it can be improved by adding a lot of organic matter such as humus or compost.

Can clematis be buried when planting?

It depends on how mature you have purchased the plant for planting. The outer part of adult clematis plants has the woody parts of the shoots. Clematis can be buried as deep as the height of the woody part, so that part of its buds are underground and give rise to new shoots. In this case, you will immediately get a thicker bush, which, of course, is very beautiful.

What to do with a young clematis?

If you buy a young clematis plant, you should never bury its greens. Buried green shoots are likely to rot, they become a very easy target for clematis pathogens. So if you are planting a clematis in the form of a young annual shoot, do not burrow it. The time to become a dense luxurious plant will still come.

Is it worth buying young plants or is it better to spend more and buy mature plants with several powerful shoots?

I buy young plants because I like to watch them gradually gain strength. However, if you want to quickly get impressive blooming luxurious clematis with lots of stems, try to choose older plants that were cut 2-3 or better yet 5 years ago. This will be noticeably more expensive, but you will get impressive clematis with lots of blooms sooner.

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