In our latitudes, oranges have always been the epitome of exoticism and Mediterranean flair. This is especially true for the patio or balcony at home. Here the orange tree provides lush greenery and - assuming good care - numerous edible fruits. But again and again the orange tree loses its leaves. You can find out here what causes this and what help actually works.
Orange tree loses leaves
There are many reasons why an orange tree loses its leaves. But only when you know the reasons can you define specific solutions and provide targeted help to the stressed and sometimes even sick plant:
Orange loses leaves during overwintering
The orange tree often loses its leaves during the winter. Since the plant is not sufficiently hardy for winter conditions typical in Germany, it is usually brought through the cold season in the conservatory or a cooler living room. If the relationship between light and temperature at the winter location is not right, the plant's metabolism will be out of balance. In order to reduce stress and to get rid of "unnecessary" ballast that needs to be taken care of, the tree sheds all its foliage within a short time. When determining the causes, a distinction is made between two completely opposite cases, which also require completely different forms of help:
warm hibernation
If the orange plant overwinters in a warm room, there is usually a disproportion between light and temperature to the detriment of the light yield. The temperatures signal a growth period and stimulate the plant's metabolism, while the light is not sufficient for photosynthesis to take place and, in addition, the UV components that are important for the plant are often removed by insulating glazing etc.
- Origin: increasing metabolic activity due to temperatures above 12 °C, but lack of UV radiation for complete photosynthesis
- Effects: Plant exhales CO2, but CO2 binding through photosynthesis is not possible, resulting in a highly exhausting metabolism and shedding of the leaves to reduce the number of plant parts to be supplied
- Remedy: reduce the temperature of the location, alternatively improve the exposure
cold hibernation
Conversely, the case is stored when the orange overwinters in a cold area. In late winter, the sun gains strength and stimulates photosynthesis. Since the cold temperatures are still a sign of hibernation, the supply of the necessary nutrients via summer root activity is lacking.
- Emergence: too much solar radiation in relation to the temperature below 12 °C, resulting in the onset of photosynthesis with a lack of water and nutrient supply through inactive roots
- Effects: Orange tree sheds leaves to restore metabolic balance by removing photosynthetic parts of the plant
- Remedy: increase the temperature, alternatively reduce the exposure
tip: Since changes in exposure are usually difficult for the layperson to implement, it makes sense to take countermeasures against leaf fall in winter, primarily by adjusting the temperature. It can be measured and regulated without great effort.
waterlogging and root rot
Although orange trees require some moisture for healthy growth and the production of fruit, they are very sensitive to waterlogging. Here the orange tree does not actively lose its leaves as a countermeasure, but they fall off as a result of damage and are therefore a clearly readable indicator. The real cause here is not waterlogging, but much more root rot. However, since this occurs in almost all cases from excessive moisture in the root area, these two aspects are closely linked and should not be assessed as separate causes.
- Development: Development of root rot due to standing moisture on the root system
- Effects: brown to black discoloration of shoots as a result of root damage and insufficient supply, premature dropping of the leaves that are no longer supplied
- Remedy: Eliminate waterlogging through good soil permeability and moderate watering behavior, additionally good ventilation of the site to remove excessive moisture on the soil surface
over-fertilization
If the orange tree loses leaves, it is usually assumed that there is a deficiency, as a result of which the orange separates from its leaves. When it comes to nutrient supply, however, the opposite can also be the case. The orange tree only needs nutrients during the growing season and then only to a certain extent. If it is exceeded, this oversupply has a negative effect on the metabolism.
- Origin: Oversupply of nutrients due to over-fertilization
- Effects: Changed osmotic pressure in the leaf cells due to disturbed metabolism, resulting in brown discoloration, drying out and dropping of the leaves
- Remedy: not possible at short notice! Reduce or temporarily stop nutrient additions and wait for new growth, repotting with soil exchange possible to eliminate nutrient reservoirs in the pot
Attention: You may be inclined to flush out the excess nutrients by additional watering after over-fertilization. Due to the intensive watering, however, there is a risk of waterlogging and root rot. In addition, the orange reacts very sluggishly and requires less water immediately after the leaves are dropped due to the lack of green mass, so that the risk of waterlogging increases even more!
fungal diseases
Like all plants that thrive in warm, humid climates, the orange is not immune to diseases, the most common of which are fungal diseases. The best known is the basic rot, in which the lower trunk segment is affected first of all. Other fungi first settle on the leaves and use this route to gain access to the organism of the orange tree. Irrespective of the specific disease, there is usually an undersupply due to damage or weakness. The first sign is almost always a shedding of the leaves, as these are the only parts that the plant can separate from on its own.
- Emergence: warm, humid climate, preferred when the plant is already weak or infested in the immediate vicinity (infection!)
- Effects: depending on the disease, infestation of roots, stems or leaves, resulting in weakening and leaf fall due to insufficient supply
- Remedy: regular inspection of the plant, use of fungicides and removal of affected shoots if specific signs of the disease are identified
parasites
First and foremost, it is lice and mites that attack the orange tree as parasites. The plant sap, which feeds these animals, is sucked out of the leaves. As a result, damage occurs due to the necessary bites, which ultimately lead to the death and fall of the leaf.
- Origin: intensive infestation of lice, mites or other parasites
- Consequences: Damage to the leaves, resulting in drying and finally dropping
- Remedy: fight the parasites with potash soap or mineral oil spray (spider mite), or rapeseed oil preparations, soft soap solution etc. (lice)
danger: Parasites attack individual leaves directly and damage them until they are thrown away. Far more serious, however, is often the access opportunity for pathogens created by the bite sites. In the event of a parasite infestation, it is always worth paying close attention to possible signs of developing diseases.
Common mistakes
Now that the common causes and possible remedies are known, it is worth taking a quick look at common errors. Because the measures taken do not always lead to the elimination of the causes. Signs are often misinterpreted, so that the orange tree is additionally burdened as a result:
No pruning!
If the orange tree loses leaves, one is quickly tempted to set additional growth impulses by pruning. However, since the orange grows very slowly, this measure puts an additional strain on it. With intensive pruning, the plant is hardly able to compensate for the cutting loss, so that growth activity and the formation of new leaves is slowed down again.
Do not increase the pouring amount!
Leaf drop is often associated with drought, especially when the drop is accompanied by browning - the ultimate sign of drought. But whether it's root rot or over-fertilization, an oversupply of water rarely helps. On the contrary, an increase in the water supply often creates another problem, which puts additional stress on the orange tree and makes the conditions for new growth less favorable.