Recent Posts

Spindle tree: growth & care

Spindle tree: growth & care

In this article, you will learn everything there is to know about planting and caring for spindle trees. On top of that, we will tell you whether spindle trees are poisonous and whether they are winter hardy. Spindle trees (Euonymus) are incredibly versatile. The intensely…

Growing begonias: planting, overwintering & tips for begonia care

Growing begonias: planting, overwintering & tips for begonia care

Begonias produce splendid flowers when cared for properly. Here you can find out everything about planting and caring for begonias with tips for extra-long flowering. Surely you have heard of the begonia (Begonia) with its one-of-a-kind crooked leaves. You have likely seen them around or…

Pruning cherry trees: the best time & method for pruning cherries

Pruning cherry trees: the best time & method for pruning cherries

When do you prune cherry trees? Is there a difference when cutting young and old cherry trees? How to cut sour and sweet cherries? Find out everything you need to know about pruning cherry trees here.

Many gardeners aspire having their very own fruit tree orchard in the garden. And a cherry tree should definitely have a part in that. To ensure the tree producing as many cherries as possible, proper care is essential. Cherry trees require regular pruning. Pruning helps cherry trees to remain full of health. However, not every cherry tree has the same requirements: the larger but lighter sweet cherries (Prunus avium), for example, are usually much more vigorous than the smaller, usually dark red sour cherries (Prunus cerasus). Both trees require a different approach to pruning. In this article, we will tell you how to proceed when trimming cherry trees and what the differences are between pruning sweet and sour cherry trees.

When to prune cherry trees?

Cherries should be pruned annually. They do not respond well to rare and radical pruning.

When to prune sweet cherries?

While most other fruit trees are pruned in late winter, summer pruning is more suitable for sweet cherries. You can prune after the harvest, which is usually between the beginning of August and the end of September. Pruning cherry trees in summer curbs too much growth, which is typical for sweet cherries. In addition, cuts heal better in warm and dry weather, making the cherry tree less susceptible to diseases.

When to prune sour cherries?

Typically for fruit trees, sour cherries thrive best when pruned in winter. Ideally cherries are pruned between November and March.

Tip: Many gardeners are afraid that their cherry tree will lose vitality after pruning. The best way to prepare the tree for pruning is regular and proper care. Fertilise your cherry tree in spring using quality organic fertilisers. A healthy and well-groomed cherry tree can usually cope well with heavy pruning without any problems.

How to prune cherry trees?

The cutting of cherry trees is extremely important if you want to grow a vibrant and abundantly-fruiting tree. But how to trim a cherry tree? Before you start the process of pruning, you should consider the needs of your tree and the aim of pruning. The following questions should help you figure out the right pruning method:

How vigorous is your cherry tree?

On the one hand, strong growing varieties will grow even stronger when pruned regularly, but will produce less fruit. On the other hand, weaker growing varieties may need to be stimulated by pruning to produce new shoots which will bear fruit on. It is therefore important to consider the vigour when cutting the cherry tree. In summary: weak growing trees can be pruned more thoroughly than their strong growing counterparts.

cherry tree orchard
Weak growing trees can be pruned more thoroughly than stronger growing ones [Shutterstock.com/Fotokostic]

How thoroughly should you prune and what effects does the strength of the cut have?

Radical pruning stimulates vegetative growth, i.e. the formation of new shoots and leaves. This can be useful if a tree hardly produces any new shoots and thus no new fruit wood. However, generative growth, i.e. the new formation of flowers and fruit, is also reduced by excessive pruning, and the tree then only reacts by forming more leaf mass.

How to prune cherry trees?

With cherries, branches are not cut just above the basis of the branch (the thickened part of the branch at its very beginning). It is important to leave a stump and not to remove all of the branch. It doesn’t matter if your goal is to just remove a branch from the middle shoots or to divert it to a side shoot. Always leave a stump of at least 7 cm in length. Cherry trees hardly ever truly heal their wounds; their wounds usually just dry up.

Which tool for pruning cherry trees?

From a certain size onwards, cherries are primarily cut with a branch saw or, even better, a fruit tree saw, and not with garden shears. The reason for this is that you usually remove whole branches and not just individual twigs. In any case, it is important to make sure that the tool is clean and sharp . If the blade is dull or rusty, the cut may fray. If, on the other hand, the blade is dirty, the wound can be contaminated – both can lead to poorer wound healing on the tree or even to infection of the cut and should therefore be avoided at all costs.

How to tell which cherry tree branches to remove?

Sour cherries in particular tend to form unwanted dominant side shoots time and again. To prevent this, proceed systematically according to the branch thickness ratio when pruning. First, the trunk and central shoot are viewed from top to bottom. If the trunk tapers at a point where a branch emerge, shorten it. The more the trunk tapers, the more the branch has to be shortened.

This also applies to the leading branches attached to the trunk. If the central branch becomes considerably narrower at one point, the outgoing side branch should be shortened accordingly. That way, you can promote shoots and branches to become leaders and create a beautiful canopy instead of a chaotic shrub.

What is the difference between pruning sweet and sour cherry trees?

Sweet and sour cherries, despite being closely related, differ significantly in their growth and are therefore pruned differently, which is why we will discuss the different methods in more detail below.

What is the aim of pruning cherry trees?

Pruning aims at various goals depending on phase of life. Formative pruning when trees are first planted differs from maintenance pruning and renewal pruning. Find the details below.

The basics of cherry tree pruning in summary:

  • Adapt the cut to the vigour of your tree: strong growing trees are cut less than weak growing trees.
  • The stronger the cut, the more the tree reacts with vegetative growth. This can impair fruit formation.
  • Never remove the branch completely, leave a stump (at least 7 cm long).
  • Cut the branches with a saw rather than with gardening shears or scissors. Remove whole branches instead of small twigs.
  • Prevent the development of too many dominant branches: shorten branches where the main shoot tapers off considerably.
  • Sweet and sour cherries are pruned differently (find explaination in the following).
cherry tree and saw
Saws are better suited for pruning cherry trees than gardening shears [Shutterstock.com/Yuliia Gornostaieva]

Pruning old cherry trees

If an old cherry tree begins to age slowly, i.e. hardly grows at all, forms little new fruit wood and accordingly bears fruit sparsely, you can encourage it to grow again by pruning for renewal. Keep in mind, though, that the tree has to expend a lot of energy on new growth, hence generative growth (i.e. the formation of blossoms and fruits) is often less pronounced immediately afterwards. But don’t worry – as soon as the vegetative growth flattens out after being stimulated by pruning, the tree’s yields will significantly increase again. This is how you prune an old cherry tree:

  1. Reduce all dead or diseased branches of the old cherry tree to stumps.
  2. Shorten the leaders to a quarter of their size, and cut back overhanging branches
  3. Remove branches that grow into the inside of the canopy or cross each other
  4. Avoid tree wounds bigger than 10 cm.
  5. Prune and rejuvenate very old trees, over several years.

Renewal pruning is best done at the end of February. However, make sure to prune only in dry, mild weather, in order to prevent frost damage on the wood.

Important: Radical rejuvenation cuts can reinvigorate old cherry trees. However, this will most likely also shorten the life of the tree, as cherries do not cope well with invasive procedures in the long term.

Pruning young cherry trees

Many gardeners believe that young cherry trees do not require pruning. The opposite is true though. It is precisely in the young years that pruning helps establish the foundation for a beautiful and even canopy. Decide on the structure of the canopy before you start pruning. Sweet cherries are best grown with spindle or pyramid-shaped canopies. For sour cherries funnel-shaped canopies work best, as they are suited for the typical multi-branch growth. Once you have made your choice working towards your desired canopy architecture starts the first year after planting. Proceed as described:

  1. Determine the middle shoot, or several central shoots depending on the desired shape of the canopy.
  2. Select several branches evenly distributed around the leader(s) for side branches. Reduce excess branches to stumps. Ideally, the selected side branches grow at a 45° angle to the leader. Unfavourable growth of branches can be corrected by tying them up or down.
  3. Shorten the guide branches of the cherry tree by about a third, making sure that the length of the leaders is equal. When training towards spindle or pyramid shape, leave the middle shoot considerably longer.
  4. Remove any buds on top of the leaders.

Cutting a young cherry tree does not stop after the first cut. Especially trees younger than 5 years still have a sparse canopy. Encourage them to branch out by pruning the young tree at least 3 years in a row. Proceed as follows:

  1. Shorten the central shoot and the leading branches by a third. Make sure that all leaders are about the same length. Always cut on a leaf bud pointing outwards.
  2. Cut off branches on the leaders that grow inwards. Leave a stump of at least 7 cm long.
  3. Regularly shorten shoots on the leading branches that grow outwards to promote branching.
  4. For the following years remove fruit wood ,leaving about four buds on a branch, from which new fruit wood then develops.
  5. Tie oblique side shoots on leaders at a 45° angle. Reduce vertically attached shoots to stumps.

Pruning sour cherry trees

As with all cherry tree pruning keep in mind to prune according to the vigour of the tree, remove the branches with a saw and with regard to the thickness ratio (as described above). When pruning sour cherries, the overall aim is to avoid the canopy of becoming too dense and bushy and to reduce the leaders to a desirable number. The ideal canopy of a sour cherry is funnel-shaped. The best time to prune sour cherry trees is between November and March.

There are two main cultivars within the group of sour cherries – the Morello cherry and the Amarelle cherry. The Morello cherry type requires its own method of pruning:

  • Morello cherry types only bear fruit on one-year-old shoots. That way the canopy quickly becomes full of bare, worn shoots that do not bear fruit the following year.
  • It is therefore essential to cut off or at least shorten each shoot that grows cherries – this is the only way to ensure enough new fruit shoots forming for the coming year. As a rule of thumb, three quarters of the fruit shoots are cut back to at least a quarter of their length.
  • Remove diseased, dead or very old wood and otherwise proceed according to the branch thickness ratio to support leader shoots.
ripe morello cherries
Morello cherry types only bear fruit on one-year-old shoots [Shutterstock.com/ Milen Vaskov Mladenov]

In comparison, here is how to cut Amarelle cherry trees:

  • On the whole, pruning this type of cherry trees tends to be less demanding, as they often develop a balanced canopy even without being pruned.
  • The Amarelle cherry as opposed to the Morello cherry does fruit even on perennial wood.
  • For this reason, the Amarelle cherries are cut similarly to sweet cherries.

Pruning sweet cherry trees

Pruning sweet cherries goes by the main principles mentioned above: pruning is carried out according to growth vigour, with a saw and with regard to the ratio of branch thickness. The aim of pruning is to maintain the dominance of the central shoot and to generate new fruit wood. Sweet cherries are cut after the summer harvest.

In contrast to Morello cherries, sweet cherry trees develop most of their fruit on short shoots, growing on annual and perennial fruiting shoots. For this reason, sweet cherry trees are cut more careully and less vigorously as to not remove any fruit-bearing wood:

  • The first step in pruning sweet cherry trees is thinning out the canopy of the tree. Cut back branches growing inwards as well as strongly branched shoots with outdated fruit wood.
  • Preserve younger branches with fruiting shoots; only remove them if they grow upwards very steep or cross or rub with other branches. By removing old and retaining new fruitwood, the younger fruitwood will produce higher quality and larger fruits than outdated fruitwood.
  • In addition, when cutting sweet cherry trees, pay attention to rotten, diseased or dead branches – remove them as well.
  • Compared to the sour cherry, sweet cherry trees have a stronger apical dominance, meaning that they grow more central on their own instead of producing many side branches. With regard to the branch thickness ratio, competing side shoots that point upwards should nevertheless be removed.
  • In the case of sweet cherries, summer pruning is particularly recommended to limit their strong growth.

Info: Fruiting shoots are the short side shoots of cherry trees, arranged in a whirl-like manner. These often carry a particularly large number of flower buds and are therefore crucial for a rich harvest.

Pruning columnar cherry trees

If you don’t have enough space for a large and protruding cherry tree, you can opt for a columnar cherry. Thanks to its slender shape, this cherry’s growth habit is ideal for smaller gardens. They can even be cultivated in a large pot. However, to ensure that the tree does not lose its elegant shape, you have to prune them. Contrary to what some might believe, pruning columnar cherries is less complicated than the pruning of its larger relatives. Columnar cherry trees do not need to be pruned regularly, but only when necessary. The following steps are a guideline to cutting back a columnar cherry:

  1. Cut back side branches that are too long, shortening them down to 10 to 15 cm in length.
  2. Always prune far above a bud pointing outwards.
  3. Remove diseased, weak or steep growing branches.
  4. The middle shoot is not trimmed for the first few years but can be shortened afterwards if necessary.

Pruning dwarf cherry trees

Dwarf fruit trees, such as dwarf cherries, are a great choice for smaller gardens, as they require little space and can therefore be grown even in tiny gardens. As with all fruit trees, the dwarf cherry tree needs regular pruning to flourish. Since dwarf cherries can also be grown with spindle-shaped canopies, there is hardly any difference in the way dwarf cherry trees are pruned compared to large fruit trees:

  1. All side branches should only grow at a slight angle to the top and are not cut.
  2. Tied down steep branches to correct their direction of growth.
  3. Thin out the canopy where branches are too dense by removing one of them.
  4. Always cut off branches above a bud and leave a stump of at least 7 cm.
  5. Middle shoots are shortened to about 30 cm above the last side shoot.
Watercress: growth, care & benefits

Watercress: growth, care & benefits

Watercress is full of benefits for human health and it is often used to refine and decorate dishes. Learn everything you need to know about growing watercress here. Watercress (Nasturtium), or yellowcress, is a species of aquatic herbs, which is often used to enrich certain…

How to get rid of aphids: aphid control & prevention

How to get rid of aphids: aphid control & prevention

There are many different ways to get rid of aphids. We will show you how to control aphids naturally and will demonstrate the advantages of organic aphid control methods. A single aphid is not a big problem; however, aphids tend to mass reproduce. As the…

Neem oil on plants: tips for using neem oil in the garden

Neem oil on plants: tips for using neem oil in the garden

Plant protection products based on neem oil can be used for natural pest control of aphids, spider mites and other plant pests. You can find out how to use neem oil to protect your plants here.

Neem oil can be used in many ways. Its use as a plant protection agent shows great potential. In the following text, we give you exciting background information and explain how you can use neem oil in your garden or at home.

Neem tree: origin & characteristics

The neem tree (Azadirachta indica) belongs to the mahogany family (Meliaceae) and therein to the genus Azadirachta. This tree is also sometimes referred to as Indian lilac or nimtree. From this, you could deduce that the neem tree originated in South East Asia. More precisely, the neem tree commonly grows in India, Myanmar, Bangladesh and Pakistan. Because the neem oil extracted from the tree’s seeds is so popular and because it grows in most arid subtropical and tropical areas, the tree is now also cultivated in Australia, America and Africa.

The neem tree can reach a height of 20 metres and an astonishing age of up to 200 years. Additionally, it is very drought tolerant. It grows rapidly and can bear fruit after only a few years. A fully-grown tree can produce up to 50 kg of fruit.

The flowers are white, and their scent is reminiscent of jasmine. The resulting edible fruits are oval in shape and up to 2.5 cm long. The seeds they consist of up to 40% oil and that is where neem oil comes from. The helpful active ingredients of the neem tree are found in all parts of the plant, but in different compositions.

Almost all parts of the neem tree are used in different ways: leaves, seeds, flowers and even the bark. For example, during the Indian New Year, Hindu believers bathe in an extract made from the leaves of the neem tree. This supposedly cleanses not just the body but also the soul. Interestingly, the branches of the neem tree were formerly used to clean teeth.

Neem oil: production of the plant protection product

The fruits that fall from the neem trees are collected and the pulp is removed. What remains are the seeds, which are processed in a variety of ways. Neem oil is can be produced using these three methods:

  • Cold pressing: The whole or ground seeds of the nimtree are gently pressed. This produces a yellow and bitter-smelling oil.
  • Water extract: Another method to produce neem oil is water extraction. Unfortunately, it is not as effective, but it is cheaper than the other methods. The ground kernels are soaked in water and an extract is thus obtained.
  • Oil extraction: Neem oil can also be extracted from the kernels. Saturated hydrocarbon (hexane) is used for this.

Many insecticidal and acaricidal substances are found in the neem tree. The former is effective against insects, the latter against arachnids such as mites.

  • Azadirachtin (the main active substance)
  • Nimbin
  • Nimbidin
  • Nimbandiol
  • Salannin
  • Meloiantriol
dried neem fruits
Neem oil can be extracted from the fruits [Shutterstock.com/wasanajai]

With an optimal extraction of the oil from the seeds, an azadirachtin content of 30% can be obtained in the oil.

Tip: If you have purchased neem oil prepared in this way, you should store it in a cool and dark place so that it does not go bad and does not lose its effectiveness.

Neem for pest control

The active ingredients from the oil of the neem tree give us an excellent opportunity to control pests on plants in a natural way.

Neem oil can be used against these pests

Plant protection products containing neem are mainly used against insects that damage useful or ornamental plants with their biting or sucking. It is particularly effective against biting insects, as it is absorbed by the insects while they feed. The azadirachtin in neem oil has an inhibiting effect on feeding and disturbs the moulting (or ecdysis) of the insects. Neem has a wide spectrum of application and can be used against the following insects:

  • Beetles (Coleoptera) like the potato beetle (Leptinotarsa decemlineata) or weevils (Curculionidae).
  • Coleoptera (Homoptera), which includes aphids (Aphidoidea) or cicadas (Auchenorrhyncha).
  • Diptera, or simply different species of flies.
  • Butterflies and moths of the Lepidoptera order, which include pests such as the box tree moth (Cydalima perspectalis).

How to use neem oil against plant pests

Primarily, azadirachtin from neem oil is effective against the larval stages by reducing production of the hormone ecdysone, which is important for the moulting of the larvae. This disrupts or delays the larval metamorphosis and prevents adult insects from developing from the larvae. The insects either die, are damaged or can no longer reproduce. In adult insects, neem inhibits the feeding activity. Death is not immediate, but the feeding stop occurs relatively quickly. As these hormones are very widespread in the insect kingdom, azadirachtin and neem are not specific, but have a broad effect. It should also be noted that azadirachtin only affects the last larval stages and some degree of damage by larvae cannot be avoided completely.

The following effects of neem oil can be observed in insects:

  • Feeding inhibitor
  • Feeding deterrent
  • Moulting and pupation disorders
  • Disturbance during egg laying
  • Reduced reproductive capacity

As the active ingredients of neem oil are absorbed by the plants, insects that do not come into direct contact with the agent but eat the plant or mine through leaves or roots can also be detected. Mining means that an insect eats inside a leaf and thus creates tunnels or mines. The absorption of the active ingredient into the plant is sub-systemic, so it is not distributed throughout the plant, but only in the immediate vicinity of the sprayed parts of the plant.

Tip: Preparations based on neem oil are particularly effective against aphids or whiteflies.

Neem oil pest control & plant protection

Important: The use of specially mixed preparations of neem oil as plant protection agents is not permitted. In the EU, only products that have been tested and approved are allowed for use. Illegal use could result in substantial fines. The same applies to the use of vinegar, rapeseed oil or soft soap on plants. If you want to use the oil of the neem tree, we recommend an approved product based on neem oil.

Neem can also be used as a powder, which is just as easy to buy as neem oil. Residues from oil production – the neem cake – can be dried and processed into powder or pellets. These products can be worked into the soil to improve it. Moreover, neem cake can be used as a fertiliser and can even combat nematodes that dwell underground and damage plants.

neem powder in a bowl
Neem can also be used as a powder [Shutterstock.com/SAM THOMAS A]

The by-product of neem oil production, the neem cake, can be used in other ways, too. The neem cake consists of the whole seeds of the neem tree, which are crushed.

This precious oil has many advantages, but like any remedy, neem oil has side effects. Some plants are sensitive to the product and lose their leaves through phytotoxic reactions. All in all, processed and diluted neem preparations are better tolerated by plants than pure neem oil.

Although it is amazing just how versatile neem is in plant protection, neem oil cannot distinguish between pests and useful species and, unfortunately, can just as easily harm beneficial insects. Beneficial insects, such as parasitoid wasps Aphidius rhopalosiphi, lacewings (Chrysoperla carnea) or predatory mites (Amblyseius cucumeris) can react sensitively to neem oil. It is therefore extremely important that neem preparations are only used in accordance with the recommendations for use on the packaging or the instruction manual. This will keep the risk as low as possible.

Using neem oil in other ways

The ingredients of neem oil can also be used for our pets. Neem oil can be used to treat wounds or to ward off insects. Neem is not only good for our plants and animals however, we can also use neem ourselves.

Important: Some scientific studies have shown that neem oil treatment can lead to some degree of discomfort and in worst cases, even symptoms like tremors in some cats. For this reason, we advise to consult your vet before using neem oil on your cats or in close vicinity to your cats.

Growing radishes: sowing, location & the right soil

Growing radishes: sowing, location & the right soil

Radish cultivation is pretty straight-forward. We will tell you what you should pay attention to when planting and sowing radishes. Radishes are at the top of the list of the most popular vegetables in summer. Whether in salads, on bread or made into a dip…

Planting Raspberries – A how-to guide to a great harvest

Planting Raspberries – A how-to guide to a great harvest

Raspberries are a healthy and sweet fruit – which grows across countries all around the world. In this short guide we will give you the most important tips on how to plant and grow your own raspberries. Raspberries (Rubus idaeus) are a true powerfood –…

Whiteflies: how to identify, prevent & get rid of them

Whiteflies: how to identify, prevent & get rid of them

The tiny whiteflies on houseplants and in the garden can be very annoying. In this article, we reveal how to get rid of whiteflies using household remedies as well as natural methods.

The term “whitefly” is a trivial name for various insects from the Aleyrodidae family. Like aphids and scale insects, whiteflies belong to the suborder Sternorrhyncha. The two most common pests in hobby gardens are the cabbage whitefly (Aleurodes proletella) and the greenhouse whitefly (Trialeurodes vaporariorum). These two species are also two of the most common whiteflies and they have a similar appearance and life cycle. But there are also some differences between them, which will be discussed in the following.

Whitefly: information & characteristics

Whiteflies are small flies, about two millimetres in size, covered with a white powder. Due to their rapid reproduction they are among those pests that are greatly feared by gardeners, just like aphids. From the egg through several larval stages to the reproduction-capable adult fly, it only takes several weeks for these insects to develop fully, especially at favourable, warm temperatures. Due to this rapid development, several generations of whiteflies are formed during the vegetation period, which lay a myriad of new eggs every day.

The larvae of whiteflies cause the most damage. They extract sap from the host plants just like aphids do. The valuable proteins are filtered out of the plant sap and a large part of the carbohydrate-rich phloem sap is excreted again in the form of honeydew. Honeydew sticks the leaves of the infested plant together. This in turn provides a perfect breeding ground for fungi, especially sooty mould, which further exacerbates the problems for the plant. By growing on leaves with honeydew, the fungi hinder the photosynthesis of the plant.

Furthermore, the whitefly can also be a carrier of various plant viruses. These plant viruses are not always very harmful to the plant: sometimes they simply reduce its beauty. Unfortunately, there is no remedy for the diseases that the whiteflies can spread.

whiteflies damage pattern
Along with damaging the plants externally, whiteflies can also carry plant viruses [Shutterstock.com/Catherine Eckert]

Often it is not infestation with the whitefly and its nutrition at the plant’s expense that poses the greatest problem. It is rather the sooty mould and various plant diseases that the whiteflies spread that can cause the most damage. The main whitefly infestation periods are late summer and autumn, as large populations are already at work at this time. If summer comes earlier and is exceptionally warm, a whitefly infestation can occur sooner than expected too.

Whiteflies: identification & damage pattern

To discover whiteflies, one must inspect the underside of the leaves of potential host plants. This is because both adult flies as well as their larvae sit well hidden on the underside of the leaves. Whiteflies also lay their eggs there. A characteristic feature of the white to yellow eggs of the whitefly is that they are laid in a ring shape on the underside of the leaf. After hatching, the whitish to yellow-green-brownish larvae are at first mobile, in later larval stages they settle down and stay in one spot. The underside of the leaves often contains flies of about five millimetres in size as well as various larval stages and eggs. When the plant is touched or moved in any way, the adult insects fly away in a typical bow-like shape.

Another key characteristic of whiteflies is the white dust that envelops them. Therefore, you can tell that there is a whitefly infestation happening by the white dust on parts of plants, the soil around the plant and, of course, on the small white insects. A sticky coating indicates honeydew excretion – if it is black, sooty mould has sadly already settled on the plant, too.

You can recognise an infestation with whiteflies by the following symptoms:

  • Two-millimetre large tiny white flies with wings
  • Ring-shaped deposit of white to yellow eggs on the underside of the leaf
  • White dust on parts of plants or the plant soil
  • Sticky coating on the leaves and possibly also black sooty mould on top

Whiteflies on plants: which plants are most frequently infested with whiteflies?

Whiteflies are not picky and have a wide range of potential host plants. In the garden, most damage usually occurs to tomatoes and cabbage.

Whiteflies on cabbage

Cabbage whiteflies infests all types of cabbages. Particularly popular among whiteflies are cauliflower, broccoli, savoy cabbage, kale and Brussels sprouts. Adult flies can hibernate on Brussels sprouts and then quickly produce new populations in the following spring. Unfortunately, even removing cabbage plants over the winter does not guarantee that whiteflies will not appear next year. Adult whiteflies might also find other cruciferous plants (Brassicaceae), such as winter oilseed rape, to overwinter on them.

cabbage whiteflies
Whiteflies love to infest various cabbage plants [Shutterstock.com/ Afanasiev Andrii]

Whiteflies on tomatoes

Tomatoes are infested by whiteflies much more frequently in the greenhouse than in the open field. The humid and warm conditions in the greenhouse are just what whiteflies need. The pests are not picky and infest all sorts of greenhouse vegetables such as tomatoes, cucumbers and courgettes.

Whiteflies on houseplants

The greenhouse whitefly in particular likes to infest houseplants. The evenly warm temperatures and lack of predators provide the whiteflies with optimal conditions for rapid reproduction indoors. Whiteflies have a wide range of different indoor plants that they tend to target, but poinsettias (Euphorbia pulcherrima) seem to be a notably frequent victim.

How to get rid of whiteflies?

If you have long been asking yourself how to get rid of whiteflies on plants, this section is for you. A heavy infestation of the whitefly can cause severe damage to the painstakingly planted and tended vegetables in the home garden. Both the damage caused by sucking the sap of the plant, the spread of sooty mould as well as the transmission of other plant diseases can only be reduced by whitefly treatment.

How to treat whiteflies naturally

Whiteflies are an annoying plant parasite, but synthetic pesticides are not necessary to control them. Especially in the house garden and inside the flat we always recommend opting for organic and natural methods of control.

An environmentally friendly and extremely effective way of treatment is to use neem oil for whiteflies. Neem-based preparations are based on oil which comes from the seeds of neem trees. The neem oil contains the active ingredient azadirachtin, which is absorbed by the insects when they suck on the plant sap. Neem preparations prevent the larvae of whiteflies from developing and the whiteflies gradually disappear.

whitefly treatment
Before resorting to harsh chemical products to treat whiteflies please consider using more nature-friendly options [Shutterstock.com/Tomasz Klejdysz]

Natural control of whiteflies with neem in summary:

  • Mix neem with water according to packaging instructions
  • Apply emulsion with spray bottle onto the affected plant
  • Young shoots are also protected by the systemic effect and do not need to be treated afterwards
  • Whiteflies are completely eliminated after two weeks at the latest

In addition, agents based on rapeseed oil or orange oil can be used to control whiteflies. The oil prevents sufficient oxygen supply to the insects and causes them to die. Rapeseed oil preparations also destroy the eggs of the pests. However, some soft-walled plant leaves do not tolerate these preparations very well.

Home remedies against whiteflies

If you are only dealing with a slight infestation, you can also use home remedies for whiteflies on plants. A frequently used household remedy against whiteflies is nettle manure. To make nettle manure, brew 500 grams of fresh nettles with five litres of boiling water. Cool the extract and then spray it onto the infested plants several times a day using a spray bottle. Another DIY way to treat whiteflies is by using soap. A soap solution of 30 grams of potash soap or 200 millilitres of liquid soap on one litre of water can also be applied to the infested plant several times a day. We recommend covering the soil around the infested plant with a thick cloth to prevent too much soap from getting into the soil.

Other options for whitefly control

Moving on, synthetic crop protection products are also available to control whiteflies. Nevertheless, they frequently contain ingredients that are harmful to the environment, the user and animals. Active ingredients such as acetamiprid do not only harm whiteflies, but unfortunately also beneficial insects in your garden. This is why we strongly recommend using natural products and homemade remedies to treat whitefly infestations. Plant protection products against whiteflies can also contain vegetable pyrethrins. These active ingredients are sadly also harmful to beneficial insects. Please, stay away from these products to keep the environment safe.

Another environmentally friendly measure in case of less severe infestation is yellow glue traps. These can be placed near infested plants. They attract whiteflies with their yellow colour and the pests stick to the traps. However, you should only use the yellow glue traps indoors or in the greenhouse, as the yellow colour can also attract bees and other pollinators. All in all, the glue traps are great for early detection of an infestation rather than for control. On their own they are not sufficient to get an infestation under control. They are great to use in combination with other natural or DIY methods we discussed above.

How to get rid of whiteflies in summary:

  • Neem oil-based products are effective and safe for the environment (be mindful of the dosage, though)
  • Preparations based on rapeseed oil are suitable for hard-leaved plants
  • Household remedies such as nettle manure and soap solutions can help with less severe infestation
  • Yellow sticky traps are great for less severe indoor infestations
whitefly control
One of the best ways to control whiteflies is to use neem based preparations [Shutterstock.com/Tomasz Klejdysz]

Whiteflies: prevention

Prevention is definitely better than cure. You can prevent whitefly infestation with a few tricks. For example, whiteflies are repelled by the smell of some plants. Thyme (Thymus), basil (Ocimum basilicum), sage (Salvia officinalis) and marigold (Tagetes) are great to use in whitefly prevention. You can take advantage of this and place plants that have already been attacked specifically next to these whitefly-repelling. You can also plant flowering wild herbs, for example cow parsley (Anthriscus sylvestris), in your garden. These flowering herbs attract beneficial insects such as ichneumon flies. Ichneumon flies are natural predators of whiteflies and will help you protect your garden.

Both in the open field and in your living space, an optimal supply of nutrients to your plants is essential. Fertilising strengthens the plant and thus makes it harder for various pests to infest it. The best way to fertilise is with fertilisers that are specifically adapted to the needs of your plant. Such products will help you meet the individual nutrient requirements of your plant. Make sure that your plant is getting a good supply of potassium and calcium for stable cell walls. For this, you should fertilise with organic nitrogen fertilisers, which at best have a slow-release effect to feed the plant gradually.

A bright and well-ventilated location for your plants, especially in the living space, can also prevent whitefly infestations. Such conditions will help your plants to grow vigorously and increase their resistance to pests and diseases.

How to prevent whiteflies in summary:

  • Grow strongly scented plants in the immediate vicinity
  • Promote beneficial insects in the garden
  • Supply nutrients to the plants with organic fertilisers
  • Grow houseplants in a bright and well-ventilated area
Fruits rich in vitamin C: top 15 immunity-supporting fruits

Fruits rich in vitamin C: top 15 immunity-supporting fruits

Many people swear by vitamin C to strengthen their immune system and get through the winter well. But which fruit is highest in vitamin C? We have selected 15 types of fruit with lots of vitamin C that you can include in your diet to…