Posted on

Climbing and climbing aids for clematis

Here are some tips on how to present clematis in the best possible light, which I would like to share with my customers and visitors to my website.

Most clematis are climbing plants, that is well known. How can I contribute to optimization and avoid mistakes in the design from the outset?

Clematis cling to anything that can be reached with their leaf stalk tendrils. These leaf stalk tendrils only need a few hours from touching to clasping. The material of the climbing aid should be as thin as possible. A thickness of 2 – 15 mm is ideal, so that 1 – 2 wraps are possible. Clematis are also able to cling to stronger material. There is then a risk that they can really “slip”. Natural materials made of wood are the most suitable because they avoid heating up in direct sunlight. Metal objects can cause slight burns to the leaf stalks in southern locations. Progressive growth is nevertheless not impaired.

Smooth climbing aids must always provide clematis with crosspieces or cross wires to prevent them from slipping down. Wire mesh fences or double wire mesh fences are perfect climbing aids, especially if they are coated. A link or eyelet chain, for example, is also ideal. This is available by the meter for little money. Fastened at the top and bottom and tensioned, the climbing aid is ready. There are countless prefabricated climbing aids in garden centers, so there is sure to be something to suit every taste. The distance to the wall must be generous, at least 7 cm.

We manufacture our own obelisks and shrub holders for clematis! They are firmly welded from 6 or 8 mm round steel. Our obelisks are modular “all-rounders” when they are joined together to form arcades, porticos or portals. Various heights and widths are possible. Individual dimensions are also possible, at no extra charge!

Here are some examples of different climbing aids.

Supports for perennial clematis

Perennial clematis do not have leaf stalks and cannot hold on by themselves! They ideally require a ring-shaped support that corresponds to the genetic growth height of the variety. This is very different for our perennial clematis. The low varieties, for example, only reach a height of 30-40 cm. The tall perennial clematis can even exceed 2 meters in height. Make sure you know in advance how tall the new perennial clematis will be so that the “support” is not chosen too low. Ring-shaped supports perform very well. The meshes must not be too tight, after all, the perennial clematis must not be completely enclosed! If there are ornamental elements or decorative spikes on obelisks, these may be slightly higher than the final height of the clematis. The decorative element will not be covered later. Other plants can provide good support. Branches of shrubs or roses provide sufficient support for perennial clematis.

Important note in this context: You must always observe the local main wind direction (see also planting under trees)

All clematis always grow in the direction of the wind, which is important to bear in mind when planting new plants and saves a lot of work later when tying up, straightening or correcting the direction of growth! This applies equally to perennial clematis and all climbing clematis! Planting on the windward side (the side facing the wind) will make things a lot easier in the future. An airy location also makes it more difficult for fungal diseases to establish themselves.

If neither a climbing aid nor a suitable shrub is available, the only option is to grow ground cover. This can be very attractive with many perennial clematis, as can be seen here with Clematis integrifolia Arabella. If you go one step further, clematis can also be used throughout the area. Strong-growing varieties such as C. jouiniana praecox or C. jouiniana Sander can cover several square meters. This goes so far that wild herbs hardly stand a chance. Slopes or embankments can even be fortified, as roots are formed where the shoots rest on the ground. (see also Propagation of ground sinks er)

Posted on

About Clematis

Questions about care, location, practice, botany, origin and many other tips

On the following pages, we address a wide range of questions from our customers. Questions about clematis in practice and botany.

Basic questions about planting and pruning clematis can be found in the guide.

Clematis are buttercups (Ranunculaceae), which also include anemones, delphiniums, Christmas roses, liverworts and columbines. Most clematis, which are widespread throughout the world, are woody perennial climbing plants. Exceptions are the perennial clematis and those clematis that must be classified as semi-shrubs.

Not only are the flowers of the clematis very beautiful and diverse, this also applies to the fruits. They have a special charm. There are bizarre, shiny or spherical shapes among them. They seem to come from another world. It’s worth taking a closer look. Impressive image motifs are available to the hobby photographer!

The fruits appear during or immediately after the flowering period and can be used as cut flowers in small bouquets. The fruits can also be used in dry binding during Advent.

Botanically speaking, clematis fruits are a covered-seeded nut. (Nuts) A woolly ball shape is formed, with the seeds arranged on the outside. Nature conservation is not neglected either. Our native songbirds use the woolly flying hairs on the seeds as padding material for breeding in their nests.

Our native clematis are: Clematis alpina, Clematis recta, Clematis vitalba and Clematis viticella (naturalized). Clematis grow in temperate climates in the northern hemisphere and are mainly found in mountainous regions of Asia. Most clematis are hardy!

Yes, there are many fragrant clematis, but only a few species have a very pronounced or intense scent. (e.g. Clematis flammula or Clematis montana). The fragrance is usually only slightly pronounced, sweetish, fruity or vanilla-like. Some Clematis montana have an intense scent of vanilla or chocolate.

Many clematis are insect and bee-friendly. The small-flowered species are particularly popular with them. The difference is that some clematis provide both pollen and nectar, while others only pollen. Bees, bumblebees and other insects need nectar = carbohydrates for their diet. Pollen = protein is mainly needed for rearing the larvae. All clematis, the seed heads were also previously pollinated by insects, logically!

Clematis are genetically capable of producing double flowers. This is particularly true of the large-flowered clematis hybrids, which originated in East Asia. Cultivars from three clematis species are particularly involved here. Clematis florida, Clematis patens and Clematis lanuginósa. Clematis florida also bloom profusely on young shoots, mainly in summer to fall. Clematis patens and lanuginósa, as well as crosses between them, flower double in spring or early summer and again in late summer, usually unfilled or semi-double. There are also exceptions that flower double in both periods. The spring flowers, some of which are densely double, appear on short shoots from last year’s wood. The double flower buds are laid in the fall and the following winter dormancy. The more favorable and longer the winter dormancy, the denser the double flowers will be in spring! The double-flowering varieties all belong to pruning group 2

Some clematis varieties luxuriate more or less strongly. This is often misinterpreted as sick or unnatural. It is a natural phenomenon that depends on the variety and the temperature. Double-flowering clematis have a greater tendency to luxuriate than single-flowering varieties. This is particularly pronounced with many Clematis viticella. With Clematis viticella `Alba Luxurians’, the word “luxuriate” is already part of the name. It is more visible with light-colored varieties and cool temperatures than with darker varieties. Occasionally only very few green “speckles” appear, as can be seen in C. Andromeda.

A complete color change is impossible. The color fades somewhat when: Extremely high temperatures or if nutrition has been neglected. A lack of light can also affect the color.

Questions keep coming up as to whether my clematis is sick? The leaves become whitish along the main veins, other leaves are variegated or some petals have a different color. The majority of these phenomena are mutations, which can be traced back to a change in the genetic material. In my many years of practice with clematis, I have discovered these two color mutations, among others. Abb. 3 shows C. Königskind blue with a small amount of pink. A new variety has been created here. (Rosa Königskind) It has the same properties as its blue predecessor. The fig. 4 shows C. Remembrance with petals by C. Comtesse de Bouchaud. This mutation originated in Great Britain. Both varieties have identical properties, in these two cases only the color differs significantly.

Mutations can also occur in clematis leaf platforms, but this often goes unnoticed. Not to be confused with different leaf shapes on the same plant. This happens all the time with many clematis.

Leaf changes in clematis

Our native Clematis vitalba has two different leaf shapes. There is a youth and an old age form here. Young plants have strongly “serrated” leaves, while older plants have “entire” leaves. The age form begins when flowering is achieved in the third year if propagation was carried out by sowing!

If there is vegetative propagation (e.g. through cuttings) as is the case with most clematis, then only the age form is visible. The juvenile form dates back a long time and only the breeder has ever seen the juvenile form.

There is no one perfect location for all clematis! A general distinction must be made here between the requirements of the individual clematis species’ native habitats. You should therefore choose the location carefully when planting.

As already mentioned, clematis are native to almost all parts of the world and, depending on their area of origin, they should also be treated here in our gardens. Most clematis prefer a cool and airy location in partial shade.

The old cliché “feet in the shade, head in the sun” is only partially true. Clematis viticella, orientalis and texensis love a sunny spot. Clematis alpina, koreana and all atragene clematis thrive very well in the shade.

Most large-flowered clematis hybrids can be placed well in a semi-shady or shady location. The site itself also requires humus-rich, permeable soil, which may need to be adapted or improved accordingly. Note: Light or white clematis are more visible in the shade than darker ones!

Most clematis are robust and easy to care for. The exception is the large-flowered clematis. They are generally considered sensitive when it comes to the dreaded clematis wilt! There are various reasons for this. Clematis can be found on many continents and have very different habitat requirements depending on their origin. If you take this to heart in advance, you won’t know any sensitive clematis. Basically: the cooler the better!

The answer is yes, there are some evergreen clematis. They mainly originate from Mediterranean climate zones (also from New Zealand) and need some winter protection here in Germany. Clematis armandii is an exception, as it tolerates the most frost (down to minus 15°).

Winter protection is only necessary for some clematis.

Clematis can live between 70 and 140 years. New Zealand’s evergreen clematis have a much shorter lifespan of only 20-25 years. Only our southern European Clematis flammula reaches a comparable age. Nevertheless, it remains present in our gardens for decades, because new seedlings have established themselves on the spot unnoticed due to the rich seed set!

There are reasons why clematis do not flower or no longer flower and what can be done about it. Incorrect timing when pruning is one cause and applies exclusively to Clematis montana, alpina and their relatives and all evergreen clematis. (see pruning guide)

Another very common cause is a disproportion between the number of roots and the number of shoots. Large-flowered clematis are particularly worthy of mention here. 2. or In the 3rd year of growth, the plant produces an excessive number of shoots, which become very thin and therefore cannot develop buds and flowers. These shoots shade each other and eventually turn yellow at the bottom and then brown. This can be remedied by removing two thirds of all shoots, which must be cut off close to the ground. The remaining shoots become much stronger and are able to flower again. C. Miss Bateman is a typical example of this phenomenon.

If clematis are very crowded by other plants in the immediate vicinity, this can also have a negative effect on their flowering behavior. Late frosts in April or May can damage the buds of the montana group to such an extent that no more buds or flowers can be seen.

An acute lack of water can cause summer-flowering clematis to flower sparsely or not at all. Similar phenomena also occur with nutrient deficiencies.

Pests can eat or damage the buds. Snails, earwigs and mice are responsible for this.

Not necessarily, you can also let clematis grow “wild”. They then become increasingly unsightly in the lower area and become more and more bare. In some places in the garden, this is certainly not a problem. A lack of pruning has little influence on the flowering behavior. Without pruning, unfortunately “the previous year’s diseases and pests” are also transferred.
Conclusion: Correct pruning keeps clematis healthier, more vigorous and more vital.

Do clematis get along with other plants? Clematis get on well with most other plants and can even be combined very well. There are countless possibilities if you consider the following. The growth height and flowering time must be coordinated in a combination. Different or similar colors should harmonize with each other and the light requirements of both partners should be tailored to each other. In order to avoid root pressure, shallow or deep-rooted plants can be used in a targeted manner. When combining with flowering plants, the question arises: flowering time together or separately? Contrast or tone on tone? It is important to remember that the background plays a decisive role in the color scheme. Light-colored flowers have a better long-distance effect than dark flowers.

Only a few clematis are suitable here. The area under a tree is naturally shady and dry. Clematis of the alpina, montana and vitalba groups(Paul Farges) are most suitable. If trees are translucent, the selection can be significantly expanded. A rhizome barrier can be successfully incorporated to facilitate the supply of water and nutrients. Practical tip from the expert: If possible, it is best to plant on the side of the tree facing the wind (windward side). (Windward side) This saves a lot of fixing work. Although all clematis grow towards the light, every wind/storm holds against them. It is important to consider the wind direction when planting. Applies not only to trees, but also to fences, archways or obelisks etc.

Division of an older perennial clematis
Root ball of an old clematis

The answer to this question is: Yes, it is possible and the following should be noted. The best time for this is during hibernation from November to February. The clematis to be replanted must be pruned back very severely for this. Special care must be taken to ensure that as many roots as possible are preserved. If this is not possible, the clematis will still survive this procedure! Depending on their age and size, they are pruned back to 20-80 cm and quickly planted in their new position. In the following year, growth slows down considerably and only returns a year later. The lost root system must first develop again. Older perennial clematis can now be divided easily.

Clematis wilt in botanical species
Wilt in large-flowered hybrids

In principle, this is possible! Clematis do not suffer from soil fatigue, as is the case with roses, for example. Replanting in the same place should be avoided if a clematis was previously affected by wilt and died as a result. This applies exclusively to large-flowered clematis hybrids. A new infection is then very likely. Many small-flowered clematis can be replanted here. Soil replacement is helpful, but is usually overrated. Most small-flowered clematis are resistant to clematis wilt, and many are even immune to this dreaded disease. In some botanical species, the infection is limited to punctiform, irregular leaf spots, which may occur latently. These clematis do not die from it. Find out more about diseases and pests in our guide!

Clematis can grow very quickly. Some varieties can grow up to 20 cm in length in one day. Clematis montana and Clematis vitalba grow the fastest. Low clematis grow considerably less, reaching 2-5 cm per day. The growth quoted here occurs after approx. 3 years, when the clematis is well established and has formed an extensive root system. Younger or newly planted clematis cannot yet achieve this. At this point, I would like to draw particular attention to pruning no. 3.

Here is an example: A Clematis viticella, with an annual growth height of approx. 2.50 – 3.00 meters, was cut back deeply and grows again to 2.50 – 3.00 meters. The growth in the spring and summer months is around 8 – 12 cm per day. After only 3-4 weeks it has already reached the length it had last year!

Clematis are divided into deep-rooted and shallow-rooted plants. The deep-rooted plants can penetrate up to 1.50 m into the soil. They have thick, golden-yellow roots that also serve as storage organs. These are Clematis hybrids, Clematis viticella and Clematis texensis. Shallow-rooted plants, on the other hand, reach a depth of 20-30 cm. These are primarily Clematis alpina, Clematis macropetala, Clematis koreana and Clematis orientalis. They have very fine-fibered roots and do not tolerate wetness!

Figures 3 and 4 show our nurse grafting of clematis. Here you can clearly see two root systems on one plant. There are remarkable advantages to this type of propagation.
Only a few clematis specialists worldwide have mastered this method of propagation. Our customers benefit significantly from our propagation method without really knowing it. Why? Thanks to the two different root systems, our clematis are able to adapt to different soil conditions. Further advantages are More vigorous plants due to the influence of the healthy Clematis vitalba as a grafting rootstock. Flowering plants in a shorter time. More resistant to diseases. Iron deficiency symptoms are largely excluded.

Carved in stone

Word creations like: Clematen, Clematisse or Clematiden are wrong and actually unbearable!

The question of the correct fertilization of clematis is often asked. The fertilizers in use today are more varied than ever before! Which fertilizer is used is a matter of opinion. What are the main differences between mineral fertilizers, stored fertilizers, slow-release fertilizers, liquid fertilizers, nutrient salts, mixed organic/mineral fertilizers, organic fertilizers, vegan fertilizers, organic stimulants and soil additives? Read more…

An important topic that accompanies us every day and always draws our attention, both on a large and small scale.

Clematis cope very well with the current extremes. In the event of prolonged rainfall, a garden can be under water for several days, as can be seen in the picture above, which is not a problem for clematis. Exceptions to this are: Alpine clematis, montana and orientalis, all of which have a fine root system.

If periods of drought prevail in midsummer and there is hardly any possibility of ensuring the water supply, the clematis will go on an “austerity course”. This manifests itself differently in the various clematis species. In many species, growth stops first. Next, the bud and flower development remains behind. The flowers appear significantly smaller than is generally typical of the variety. Finally, the lower leaves turn yellow then brown and eventually fall off prematurely. This continues rapidly from the bottom to the top. This process is accelerated by a lack of nutrients. There is often a misjudgement that indicates possible illnesses.

Instead of long dry periods, short-term heat damage can also occur. (Photo top left) This is particularly the case if, after several weeks without direct sunlight, heat waves suddenly occur again, accompanied by direct sunlight. Even Clematis texensis, which are ideally suited to sunny locations, can be damaged. Brown flower edges or leaf necrosis indicate such damage. Unfortunately, climate change also brings new pests. (photo top right)

All climbing clematis require a climbing aid. These can be very different materials. Artificial climbing aids such as trellises, fences or obelisks are used. Other plants, trees or shrubs are readily accepted by clematis as natural climbing aids. They hold on by themselves with the help of leaf stalk tendrils. Perennial clematis cannot hold on by themselves and need a “hug“.

There are numerous clematis that have been introduced from other continents and cope well with our climate here in Central Europe. I am not yet aware of any clematis species that can be classified as anything close to invasive. Our native Clematis vitalba could become a nuisance. With orientalis, alpina, intergrifolia or viticella, individual seedlings may be visible here and there. However, there can be no talk of an “invasion” here.

Cut a shoot and take a close look at the cross-section. If the cross-section is green, then the clematis is alive. Another method is to remove the bark with a sharp knife. Then green should also appear underneath – i.e. alive! If brown is visible in both cases, then the shoot in question or the entire plant is no longer alive. Life can also be recognized by whether a shoot is brittle or elastic when bent. Elastic means alive. In winter, signs of life can also be seen on the axillary buds (nodes) if these are clearly visible. With our perennial clematis it becomes more difficult to recognize life. All above-ground parts of the plant die. Live buds are located 2-5 cm below the soil surface or below the edge of the pot. You could compare it to an “asparagus” in miniature form.

Posted on

Planting clematis

Clematis Pflanzung

The basics of planting clematis so that you can enjoy them for a long time. Clematis can be planted all year round as long as the ground is not completely frozen.

The best time to plant clematis in the garden is August to October. This is directly related to the annual rhythm, root formation and soil temperature.

The soil temperature plays a decisive role here, as does the appropriate soil moisture, which goes without saying!

This planting date is considered optimal not only for clematis, but also for many other plants.

In contrast to air temperatures, soil temperatures fall only slowly in the fall. A certain amount of heat from the summer months is still “stored” in deeper layers of soil. We take advantage of this for the fall planting. At a depth of 20-30 cm (trench depth), the soil temperature is still above 10°. In such conditions, the plants will still form new roots and your clematis will grow shortly.

When planting, the planting hole should be one spadeful in size and depth. Do not forget to water after planting! Do not water in or trample down! Lightly pressing down is sufficient. The soil must be rich in humus, loose and well-drained! At the same time, it must be able to store moisture. If your garden soil does not provide this, you should take measures to improve the soil. There are numerous soil improvers available from specialist retailers. The following products are available: Various rock powders, compost, lava stones, pumice, bark products, wood fibers, coconut fibers, rice husks, expanded clay and much more. Peat-free substrates are also available and are on the increase! In recent years, potting soils and substrates with mycorrhizal fungi, Bacillus subtilis and Trichoderma harzianum have also increased significantly. These substrates with microorganisms support root formation and prevent the spread of harmful fungi in the soil! We have been supplying our clematis with these microorganisms for several years now.

Planting depth

Clematis hybrids, Clematis viticella, Clematis texensis and Clematis perennial forms should be planted deep enough so that one or two pairs of eyes are included in the soil, which is about 5-7 cm deeper than they were previously cultivated in a pot. Clematis alpina, Clematis montana and Clematis orientalis are planted a little higher. This is helpful so that they do not suffer badly from moisture!

The planting distance

Planting on walls or fences. The distance from plant to plant is approx. 1/3 of the growth height, which in many cases is 0.80 – 1.20 m. The distance to the wall plays a subordinate role and can be approx. 20-30 cm. A distance of 30-40 cm from other plants, such as climbing roses, is sufficient. You can plant 2-3 clematis together directly on pergola posts and obelisks. The prerequisite here is light from all sides.

Finally, the planting site is ideally covered with bark mulch. It is important preferably use sterile mulch material made from pine or pine bark instead of using mulch from hardwood or mixed forest!

Pine bark lasts for many years and is preserved by the tree resin content.

Planting in containers

You can also plant clematis in tubs and containers all year round. The potting soils and substrates should also meet the same criteria as those to be used for outdoor planting. A coarse structure and good water drainage are important. Most clematis can remain in the same container for several years. The larger and deeper the container, the longer the clematis can stay in it. The minimum volume is 10 to 12 liters of soil per plant per year. The dwarf varieties with the longest possible flowering periods or perennial clematis are best suited. Strong-growing varieties are less suitable. The container should contain at least 20 liters of soil. The bigger, the better. Depending on the characteristics of the variety, you should also use a climbing option for the clematis.

Casemate, top winter storage

Overwintering clematis in containers. Most clematis can manage without additional winter protection, while some other clematis varieties require winter protection. This is the case with the florida and cirrhosa varieties, for example. It is often sufficient to place the container with the clematis in a frost-tempered place or to protect the pot with a fleece before heavy frost sets in. In addition, watering over winter is hardly necessary. The substrate is often frozen dry after long periods of frost. Therefore, a little water is added again after thawing.

Posted on

Clematis diseases and pests

Krankheit und Schädlinge

What diseases and pests can occur in clematis?

Clematis diseases

Clematis wilt = Phoma Clematidina (former name Ascochyta Clematidina)

The No.1 topic in the cultivation of clematis. All clematis can be affected, but mainly large-flowered hybrids can perish. In the case of small-flowered species, there is usually only a latent infection that is hardly noticed. Such affected clematis are resistant or even immune and do not die from it! Phoma is a vascular parasitic fungal disease that can affect all parts of the clematis plant. (leaves, stems and roots). This fungal disease is usually introduced unnoticed. The leaves are always infested first! This initially manifests itself as small irregular spots in the lower part of the “new” clematis. An infection attacks from the underside of the leaf and then penetrates the entire leaf tissue, which eventually turns brown and dies.

Phoma on clematis hybrids

An infection progresses quickly from the bottom up. Temperature, light conditions and the presence of water play a decisive role here. The fungal spores may also have been carried over many kilometers or come from the immediate vicinity. The fungal spores can only establish and sprout if water is available for several hours and temperatures are well above 20°. Other infection factors are: Damage to shoots, especially near the ground, or direct root damage if fungal spores have been washed into the soil. This infection often occurs in the second or third year after planting. The latter always happens if a leaf infection has previously occurred or the newly purchased clematis has already brought the fungal spores with it in the pot. When buying new plants, particular care must be taken to ensure that the lower leaves do not have any brown spots, however small they may be. Once the disease is present, it is almost impossible to combat.

The only way to permanently establish healthy clematis in the garden is to use small-flowered clematis species and their varieties!

Phoma on botanical species of clematis

What can be done to prevent this disease? The highest priority is to purchase healthy plants. If possible, position the clematis so that the foliage can dry quickly after rainfall.
Water and irrigate in such a way that the foliage remains dry. Choose an airy and cool location, because the cooler the better. Wind movement also helps to keep clematis healthy. If you recognize the first signs of a leaf infection, it is helpful to remove the infected leaves immediately.
Control measures can be initiated with various fungicides.
Fungicides that are commercially available against various leaf spots can be used. Biological agents are also available. Here, Trichoderma fungi and Bacillus subtilis are the most common and available antagonists. Various plant strengthening agents can also be used to help.

Powdery mildew

Powdery mildew
is widespread and occurs on many other plants. Native shrubs, perennials and ornamental plants can also be infested. Fortunately, only a few clematis are affected. The weather has a major influence on the spread of mildew. In clematis, infection usually begins in late summer or fall. As winter dormancy is already imminent at this time, major damage is not to be expected. Powdery mildew penetrates the surface of the leaves and can be recognized by a mealy, white coating on the stems and then on the leaves. Later, flowers can also be infested. Black spots become visible in the late stages. Powdery mildew is still easy to combat in the early stages. If you wait too long, it becomes much more difficult to eliminate mildew.

Downy mildew

Downy mildew
differs from powdery mildew in that it is mainly found on the underside of the leaves and penetrates much deeper into the plant tissue. This is a rather gray coating that looks furry. The upper side of the leaf turns pale green, then yellow and later brown-black. Downy mildew rarely occurs.

Botrytis, gray mold

Gray mold
is a weak parasite and occurs primarily in high humidity. A lack of light can also lead to the spread of gray mold (Botrytis). This usually first manifests itself on the older leaves in the lower part of the plants. Young shoots can also be infested under extreme infestation pressure.

Phytophtora, Rhizoctonia and others.

Various root diseases
such as Pythium, Phytophthora, Rhizoctonia and Fusarium can damage clematis in the root area. These diseases are often confused with clematis wilt, because at first glance they look similar. The diseases mentioned can occur on many cultivated plants or be introduced by them. Clematis collapse within a short time after infection. Waterlogging and insufficient drainage are often the causes.

Clematis pests

Nudibranchs + egg clutches

are the main enemies of clematis. It is mainly slugs that can cause major damage to clematis. Whole shoots fresh from the soil can be damaged just as much as leaves or flowers. Snails are nocturnal and hide near the plants in dark, damp places during the day. Control: In addition to collecting at dusk, chemical agents are also available. Plant pathogenic nematodes can be used for biological control.

Important to know!
There are also “useful helpers” among the slugs. The tiger snail. It eats other nudibranchs and their eggs. Furthermore, it lives only on dead plant parts and fungi. Not from green plant material! It should not be removed under any circumstances. Look out for them on your next garden tour. Not all nudibranchs are the same. Unfortunately, far too few garden owners are aware of this.

Weevils + larvae

Weevils and their larvae
For many years I have been observing the large spread of weevils on numerous crops. These persistent problem pests are mainly found on hard-leaved plants. When I look at rhododendrons, in gardens or in public green spaces, it becomes clear how big the problem can be. Roses and many garden shrubs can also be infested.

So far, the damage to clematis is still minor, but it is important to keep an eye on the problem. Typical is the feeding on the leaves. The nocturnal beetles cannot be seen during the day and only come out at dusk. Worse are actually the larvae of weevils, because they feed on the roots or the root collar. Growth depression is the result and the resulting wounds create entry points for fungal diseases.

There are very effective biological agents for controlling weevil larvae.

Black aphids are “milked” by ants
1st generation aphids with wings

can occur on all cultivated plants. They cause damage by sucking on the plant sap. The first generation of aphids to hatch from the winter eggs is winged and spreads through our gardens at the end of April. One wonders where they suddenly come from. Wind and rain transport the aphids over several hundred meters. Later in the summer, ants can also spread the aphids. If the infestation is severe, the shoot tips and leaves can be affected and stunted. Because many aphids are greenish, they are often only recognized late. Natural enemies are our small songbirds. If you create nesting opportunities, you will hardly have any problems with aphids. The same applies to harmful caterpillars. (see next article) Aphids are easy to control; if you want to get by without chemicals, you can use biocides.

Caterpillars from various Moths

cause feeding damage in the period from May to October. The misshapen feeding holes are clearly visible and can be mistaken for snail feeding. However, no traces of mucus are visible here. They usually hide on the underside of the leaves and are not noticed. The control is comparable to the control of aphids. Many pesticides are effective against both sucking and biting insects.

Phytomyza clematidis adult fly

For several years we have been observing a strong increase in Phytomyza clematidis

A fly whose larvae cause crippling of the flowers. It has spread northwards from southern Europe. There is a certain time window during which the fly is active, by piercing the still closed flower buds and laying its eggs. The larvae hatch from these and eat the stagnant vessels while the bud is still closed. Even the buds themselves are not spared. They are slightly curved or misshapen. As time goes on, the crippling becomes more and more obvious. The time window for this damage is the month of May and this only becomes apparent in June, for example when Clematis viticella opens its first flowers. Clematis that flower earlier or much later are not affected. Control can also be carried out with various insecticides or biocides. Timely or preventive treatment is particularly recommended here.

Mice are unloved guests

Various types of mice such as voles, field mice or house mice can cause damage to clematis. Voles feed on the roots and the result is that the clematis no longer grow quickly or stagnate. Occasionally they perish completely. Field mice or house mice feed on the above-ground parts. The stems are gnawed through and the sap flow is interrupted. A “withered appearance” becomes visible. The clematis looks as if the shoots have been cut through.

Other pests that can occur on clematis are earwigs, thrips, flower thrips, rapeseed weevils and spider mites.

Posted on

Clematis pruning recommendations

Pruning is an important topic for the successful cultivation of clematis!

Regardless of the planting date or the later flowering date, you should carry out a so-called “pruning”. The newly planted clematis should be cut back approx. 20-30 cm above the ground in November or December of the year of planting. In the case of spring-flowering clematis, for example, it is best to forgo the few flowers in the first year and think about a well-branched, bushy and vigorous plant in the long term.

The following pruning rules are then followed in subsequent years.

Clematis experts, gardeners, hobby gardeners and authors of books all agree that all clematis are divided into three different pruning groups. These cutback groups are labeled 1, 2 or 3 or A, B or C.

There is widespread disagreement about the date of pruning, especially with pruning groups 2 and 3, the question arises as to when to prune. Pruning in late fall or spring? Both are possible! Everyone must decide for themselves when to prune. There are advantages and disadvantages to both options, but I recommend pruning in November/December.

Clematis pruning – Group 1

Do not prune is often the recommendation – but this is not quite the right way to put it.

It would be more correct to say: pruning yes, in May-June and not in November-December.

This rule applies to numerous spring-flowering plants as well as wild species and their varieties. This primarily includes the entire C. alpina (atragene) and C. montana. Both groups of species lay their spring buds in the summer and fall of the previous year. The flowering period itself then begins the following spring after the winter dormancy. Young leaves and flowers then appear at the same time. This development is called “flowering on the previous year’s wood”, a common phenomenon in woody plants such as forsythia or fruit trees.

All spring-flowering plants tend to senesce, so it is all the more important to prune them at the right time! Cut back to the desired size. The plants then have enough time to grow and produce buds for the following year. Partial pruning is also helpful, especially in the case of Montanas, which can be limited to a few shoots of different lengths.

Clematis pruning – Group 2

Clematis pruning - example pruning group 2

Cut back lightly every year in November/December (shorten all shoots by half). This is a pruning height of approx. 60 cm to 120 cm above the ground. Cut back younger clematis at 60-80cm, older clematis between 80-120cm. Use on clematis hybrids that flower twice a year. In my descriptions, these clematis are listed with flowering dates of 5/6 (May-June) and 8/9 (Aug.-Sept.). Heavy pruning to 30-40 cm above the ground is recommended every 4-5 years to rejuvenate the clematis and keep it vital.

All clematis hybrids in this pruning group flower in spring in the lower section on the short shoots that emerge from the “previous year’s wood”. After the first flowering period in spring, new shoots (long shoots) are formed, which then flower again in summer/late summer.

Many double-flowering clematis hybrids only produce double flowers on these short shoots in spring!

The second flowering period in summer/late summer is often unfilled or semi-double in such clematis varieties. There are some clematis exceptions that also flower double during the second flowering period, e.g. Multi-Blue.

Typical of these clematis varieties is the abundant fruit set after the first flowering period. These fruits should be cut off and removed together with the pair of leaves underneath, so that the shoots will grow back quickly and the new shoots will then flower profusely again in about 6 weeks!

Clematis pruning – Group 3


Cut back all shoots vigorously every year in November/December (to 20 to 50 cm above the ground). Used for numerous Clematis hybrids and Clematis wild species that flower exclusively in summer. All these species and varieties produce long shoots that end in a mass of flowers. These include, for example, Clematis viticella, Clematis texensis or Clematis hybrids such as Jackmanii or Rouge Cardinal. Without pruning, such clematis would become more and more bare from below. Certainly not harmful in some planting positions, e.g. with shrubs or climbing roses, i.e. the pruning height can be individually adapted to the local conditions.

Posted on

Fertilizing clematis

The question of the correct fertilization of clematis is often asked. The fertilizers in use today are more varied than ever before! Which fertilizer is used is a matter of opinion. What are the main differences between mineral fertilizers, stored fertilizers, slow-release fertilizers, liquid fertilizers, nutrient salts, mixed organic/mineral fertilizers, organic fertilizers, vegan fertilizers, organic stimulants and soil additives?

Overview of the various fertilizer substances that are commercially available

Fertilizer preparationDuration of effectMechanism of actionAdvantagesPractical tip
Mineral fertilizer Complex fertilizer2 – 3 weeksWater-soluble granules, dissolves quicklyFast initial effectNo long-term effect
Stock fertilizer Complex fertilizer6 – 12 weeksGranules dissolve slowly over timeEasy to useHardly any overfertilization
Slow-release fertilizer Complex fertilizer3 – 12 months depending on the preparationCoated fertilizer with membrane effectContinuous nutrient releaseFamiliarization helpful and improves the effect
Liquid fertilizer Complex fertilizer5 – 7 daysDissolved in irrigation waterImmediate effectShort effect
Nutrient salt complete fertilizer, single-nutrient fertilizer7 – 14Dissolve in the irrigation waterHigh percentage, quick effect Very economical!No long-term effect
Mixed fertilizer, organic-mineral Complete fertilizer3 – 6 weeksGranules, partly water-soluble and microbiologicalEasy to useLow nutritional values
Organic fertilizer Complete fertilizer or single-nutrient fertilizer3 – 30 weeksMicroorganisms convert the substance into plant-available nutrients.Simple application, low salt contentIncorporate, low nutritional values.
Vegan fertilizers Mostly complete fertilizers2 – 12 weeksMicroorganisms convert the substance into plant-available nutrients.No salt damage, low Co2 loadIncorporate, low nutritional values.
Bio-stimulants 1 – 3 different componentsUp to one yearSoil fungi and bacteria that occupy niches and form symbiosesWithout chemical additivesSome highly effective substances
Soil – additives Mostly one substance6 – 18 monthsWater reservoir, air reservoir, loosening upIs helpful for soil improvementMany different substances are available
Lime (PH value increase)

6 – 8 monthsWater-soluble, powder or granulesImproves soil lifeImportant cell building block! Indispensable for acidic soils!
Trace elements,
Micronutrients such as: Mg, Fe, Cu, B, Mn, Mo, Zn
3 – 6 months
in most
Contains complete fertilizers
Water-soluble powder
or liquid
Improves leaf coloration, assimilation and many important processesIndispensable cell building blocks

I have deliberately refrained from naming individual preparations here, because everyone prefers a favorite fertilizer that is used. Rose fertilizer, perennial fertilizer, flower fertilizer or tree fertilizer can be used. You can get them in garden centers, country stores, DIY stores, nurseries or discount stores.

When fertilizing clematis, it is important to use a dosage that is adapted to the plant’s development!

The manufacturer’s instructions must be strictly adhered to, because a lot does not help a lot!

Complete fertilizer

Complete fertilizers (NPK), as the name suggests, contain all the main nutrients and trace elements! The various types of fertilizer differ in their composition, sometimes significantly. The higher the numbers, the higher the fertilizer yield!

Example: NPK stands for: N = Nitrogenium Nitrogen, P = Phosphorus, K = Potassium. The letters are accompanied by numbers that indicate the percentage of the individual nutrients.

After prolonged rainfall, it makes sense to top up with a single-nutrient fertilizer, as N = nitrogen and Ca = lime in particular are quickly washed out and are no longer available to the plants. Yellowing is the result and increases rapidly.

A very popular, pure nitrogen fertilizer is horn shavings. It can take several months before the desired fertilizing effect is achieved, as soil organisms must first convert the substance and make it available to plants. This depends particularly on the temperature and humidity. The misconception that horn shavings alone are sufficient as a fertilizer is clearly answered at this point with “no is not enough”.

Organic fertilizer

An important note on the popular organic fertilizers. Most of these fertilizers come from factory farming. (horn meal, horn shavings, bone meal, guano, etc.) For example, the use of sheep’s wool as a fertilizer is new. Vegan fertilizers are becoming increasingly important. The use of green manure (alfalfa and legumes) should not be ignored either.

This contrasts with today’s high-tech fertilizers, which are becoming ever more sophisticated and efficient, also in terms of environmental compatibility and groundwater protection.