Citrus tree care from A-Z for healthy citrus trees

The citrus tree belongs to the Mediterranean and evergreen plants. The botanical name 'Citrus' is related to the Greek word 'krèdos', which means 'tree with fragrant wood'. These plants impress not only with their external appearance, but also with their aromatic scents. In a sunny location in summer, the essential oils contained in the leaves evaporate and give off an intense, fresh, fruity scent. The lemon blossoms and fruits smell rather sweet but still pleasant.

Care

Due to their limited winter hardiness, citrus trees are usually kept in pots or tubs, where they become eye-catchers on patios and balconies. An optimally cared for lemon tree has a closed growth and a rounded crown shape. While it grows up to 700 cm in height in its natural home, it stays much smaller in the pot with a size of up to 130 cm, which doesn't make it appear any less attractive.

The most important factor in care is overwintering. If the right winter quarters are found and the requirements of this plant are optimally implemented, that's half the battle. Nevertheless, site requirements and care measures such as watering, fertilizing and cutting should neither be underestimated nor neglected.

Location

As subtropical plants, citrus trees are real sun worshipers who want to be outdoors for as long as possible. A permanent attitude as a houseplant is also possible but not recommended. The foliage would lose its rich green colour, as this requires a lot of light, which can only be guaranteed outdoors. In addition, there is often no flowering and thus no fruit set. Another point that speaks against keeping them exclusively indoors is the higher susceptibility to pests.

• Preferably put outdoors from around April to October
• Location should be warm, sunny and sheltered from wind and rain
• The blazing midday sun in summer should be avoided
• Consistent temperatures in the crown and base area are recommended
• Temperatures around 25 degrees optimal
• If you keep them indoors, choose a location with a south-facing window if possible
• Spray regularly with room temperature water to increase humidity

Floor

The citrus tree needs loose, well-drained soil with a high humus content. There are special soils for citrus plants on the market that are optimally tailored to the requirements of these plants. Those who prefer to mix the soil themselves can do so by mixing peat, compost and garden soil and adding coarse-grained components such as gravel or expanded clay to ensure good permeability guarantee.

Pour

Citrus trees need to be watered regularly. The most important thing is to find the right balance, because these plants should not be watered too much or too little. Unfortunately, in most cases it is actually the case that too much is poured. If the substrate is dry, it must be watered properly and thoroughly. Before the next watering, let the upper layer dry to a depth of about 1.5 cm. It is best to water it abundantly at larger intervals. A moisture meter can prevent a lack of water but also waterlogging.

Until now, citrus plants should only be watered with low-lime or lime-free water. In the meantime, scientific studies have found that this is not fundamentally correct, because citrus plants also need calcium. Therefore, they should preferably be watered with tap water, which should not be administered directly from the tap, but should be stale. Stale because the water is too cold when it comes out of the tap and the plants could be very sensitive to it.

Fertilize

In order to thrive, bloom and produce fruit, the lemon tree needs sufficient nutrients in addition to water. If you repotted at the beginning of the year, you can do without additional fertilizer in the first few weeks. Otherwise, a high-quality citrus fertilizer should be administered every 1-2 weeks from the start of budding until September, if possible via the irrigation water. Tap water supplies the plants with calcium, so that the plants are optimally supplied with all important nutrients and trace elements. Calcareous tap water also has the advantage that a frequently occurring iron deficiency and so-called chlorosis can be prevented.

hibernate

The right winter quarters

Basically, a citrus tree should be moved into winter quarters as late as possible and back outside as early as possible. Depending on the region and the weather, it is time to bring them indoors from around October, but in any case before the first frost.

• Classic winter quarters are unheated but frost-free greenhouses or conservatories
• Cool adjoining rooms with sufficient brightness are also suitable
• When there is limited light, plant lamps can help
• Heated living spaces are unsuitable for wintering
• Reasons for this are lack of light, too high temperatures and too dry air
• At best, hibernation is bright and cool
• Temperatures between 5 and 10 degrees are optimal
• The winter quarters should be all the brighter the warmer it is
• On cold floors, place the plants on a styrofoam plate or coconut mat
• This prevents the root ball from cooling down too much
• Also ensure good ventilation without draughts

care in winter

At hibernation temperatures of 5 - 10 degrees, citrus trees enter a dormant phase. Their metabolism is reduced, so that the roots almost cease to be active. As a result, the need for water is significantly reduced. If, on the other hand, the temperatures rise above 10 degrees, the metabolism is activated and the vegetation of the plant is set in motion. Since the citrus tree needs light for photosynthesis, which is only available to a limited extent in winter, it reacts by shedding its leaves.

This shedding of leaves is often wrongly associated with a lack of water. There is more watering, which makes the problem even worse, because the less foliage there is on the plant, the less water it can evaporate. The result is a permanently wet substrate, which can lead to root rot and, in the worst case, to the complete death of the plant.

Therefore, attention should be paid to low temperatures and moderate watering. Usually it is enough to water the citrus tree every 4-6 weeks. In addition, occasional spraying with lukewarm water is recommended. There is no need for fertilizer at all, because the roots can grow at these low temperatures Nutrients do not absorb, they would have no use for the plants and would mostly with the irrigation water flushed out.

Pruning measures before wintering out

Basically, when pruning citrus trees, less is more. It is best to cut as little as possible and as much as necessary. A distinction is made between maintenance and training cuts. The best time for both types of pruning is late winter or early spring. the early spring, the citrus tree has the whole season to compensate for the lost substance and form new shoots.

While maintenance pruning, as the name suggests, serves to preserve the plant and can go as far as the green wood, the training pruning has the development of a strong and stable basic structure and the early development of the crown Goal. In the case of older specimens that have not been trimmed for a very long time and are already heavily bare, a rejuvenation cut can also be an option.

maintenance cut

• The maintenance cut is about, among other things, thinning out the crown a little
• To do this, cut out too dense, damaged and diseased shoots
• Always remove the weaker shoots from crossing shoots
• Always cut off shoots completely and directly at the base
• If only shortened, they branch out again and thicken the crown
• Leave only one of two equally strong shoots from a branch
• Shorten outer branches by a third above a side branch or bud
• Cut fruit-bearing branches in half after harvest
• This allows new fruit wood to form again

In the case of a citrus tree that has been damaged by frost or pests in particular, pruning back into the new wood can be advisable. On the one hand, the interfaces can be better encapsulated and on the other hand, the growth power then concentrates on the new, unstressed wood.

education cut

When pruning for training, you should always cut above the bud of a branch or in the case of lateral branches at the base of the next thicker branch. The so-called lateral drives are shortened by about a quarter of their total length. In addition, all competing shoots, crossing shoots that grow inwards and shoots that grow steeply upwards are removed. Of course, dead and diseased wood is cut out again and again to ensure good ventilation of the inside of the crown. Finally, the main shoot is shortened so that it overhangs the other side shoots by about 10-15 cm.

Rejuvenation pruning of older citrus trees

Little or no citrus trees that have been pruned for a longer period of time will eventually come to that bald that they only have leaves on the tips of the shoots and hardly any new growth is recorded. Then it's time for a rejuvenation pruning to revitalize the citrus tree. To do this, you cut back all the stronger branches so far that a 10-15 cm long stub remains, from which the lemon tree will then sprout again. The stronger the pruning, the stronger the plants will sprout again afterwards.

Torn bark at the interfaces should then be straightened with a sharp knife, otherwise germs and bacteria can quickly settle and damage the plant. After such a pruning for rejuvenation, fruit yield is not to be expected for at least a year. In order to prevent the plant from becoming bare again, the newly formed, still herbaceous young shoots are shortened again to 30-40 cm so that they branch out better.

Repot after cutting

In addition to cutting, repotting is one of the first things to do in spring. This ensures permanently vital plants, beautiful flowers and fruit yield. Young lemon trees should be repotted into fresh soil every year and older ones about every 2-3 years, at the latest when the roots grow out of the drainage holes. The plant substrate and the choice of the right planter play an important role.

• The substrate should be water-permeable, structurally stable and rich in nutrients
• Ideally use special citrus plant soil
• Or a mixture of good garden soil, quartz sand and broken gravel
• When choosing the planter, give preference to pots made of clay
• Clay pots are more stable than plastic pots
• The fine pores in the clay ensure minimal ventilation of the root area
• Pot should be a third larger than the root ball
• or approx. 2 cm in diameter larger than the old pot
• The bottom layer is a drainage layer several centimeters thick
• Fill in some substrate
• Then place the citrus tree in the middle of the new pot at the same height
• Fill with fresh substrate, press down and water vigorously

when outside

Even if the lemon tree should go outside again as early as possible, there is no getting around a short acclimatization phase. Exactly when that is again depends on the region and weather conditions. In any case, the nights should also be frost-free. First, the plant is only placed in a shady spot for a few hours during the day. Direct sunlight should be avoided at all costs, as it would burn the relatively sensitive leaves of the citrus tree. The duration of the outdoor stay is gradually extended and the location becomes a little sunnier, until the plant can finally be placed in full sun again.

multiply

cuttings/cuttings

Only healthy and strong mother plants should be used to propagate cuttings. You cut, if necessary during the annual pruning in early spring, 10-15 cm long, semi-lignified cuttings of shoots from the previous year. You should have several buds and 1-2 small leaves at the tip of the cutting. To minimize evaporation, the remaining leaves are shortened by about half.

It is best to cut the cuttings at an angle, this makes it easier for them to absorb water. Now you put them with the interface in a rooting powder and then about 4 cm deep in small pots with potting soil. The cutting is pressed firmly into the substrate and the substrate is moistened.

Then you put a translucent plastic bag over the cuttings or cuttings. the pot and put the whole thing in a warm and bright place out of direct sunlight. The plastic bag should be removed daily for a short time to prevent mold and rot on the citrus tree. The potting soil should not dry out at any time, but it should not be too wet either. As soon as new growth appears, the foil is removed. If the pot ball is well rooted, it is repotted.

sowing

Only seeds from fresh and fully ripe fruits should be used for sowing, which can be bought in almost every supermarket. It is best to use small plant pots with appropriate drainage holes.

• On the bottom of the pot first a layer of smaller pebbles as drainage
• Commercial growing soil is then applied
• Put one or more lemon seeds about an inch deep in the ground
• Then moisten the substrate and put the translucent foil over the pots
• Then put it in a warm and bright place out of direct sunlight
• It takes about 4-6 weeks to germinate
• Substrate must be kept evenly moist without being permanently wet
• When the seedlings are about 10-15 cm tall, separate into small pots
• It takes at least five years for the first flowers and fruits to appear

diseases and pests

root rot

Too much and prolonged wetness can lead to root rot, as a result of which the plants lose leaves and fruit. If it is detected early, repotting may save the plant. As a preventive measure, care should always be taken to ensure an airy substrate and appropriate watering behavior.

leaf discolouration

Yellowed leaves on the citrus tree can be the result of too much or too little water. The pouring quantities should be adjusted accordingly. Occasional yellow leaves are not a disease but completely normal. If necessary, the citrus tree must be thinned out a bit so that more light can get into the crown.

scale insects

Pest infestation mainly occurs if the winter is too dark and too warm. Scale insects can be easily wiped off with a cotton swab soaked in alcohol. In the case of advanced infestation, chemical agents e.g. B. be used in the form of sticks for combating.

Mealybugs and mealybugs

Mealybugs on the citrus tree can also be removed with a cotton swab soaked in alcohol. In addition, natural predators such as lacewings, ladybugs or parasitic wasps can be used or, in the case of a severe infestation, appropriate chemical agents from specialist shops.

spider mites

In the case of spider mite infestation, showering with a stronger jet of water can already eliminate most of the pests. The undersides of the leaves of the citrus tree in particular should not be left out. In addition, spraying with plant decoctions or neem oil preparations is recommended. Lacewings, ladybirds, predatory mites and gall midges also do a good job.

Conclusion

Citrus trees are visually impressive with attractive foliage, fragrant, white flowers and, under optimal conditions, also with ripe fruit. They conjure up a Mediterranean flair on terraces and balconies. Despite everything, these plants are quite demanding in terms of site conditions and care, which should be considered before purchasing to avoid disappointment. In principle, however, they are worth every effort.

Learn more about potted plants