Cestrum nocturnum, most commonly known as night-blooming jasmine, is a gorgeous vine or shrub which is characterised for those exquisite white to yellow trumpet like flowers which are amongst the most scented in all Jasmine vines. Although this jasmine plant is not too complicated to care for, pests, such as, spider mites or poor watering techniques, may cause its leaves to turn yellow and loosing its famous deep green foliage. So, what are the causes and what do you do when jasmine leaves turn yellow?

In this post we cover the different reasons why your jasmine plant leaves are turning yellow and how to fix them.
In this post we cover the different reasons why your jasmine plant leaves are turning yellow and how to fix them.

Night blooming jasmine plant leaves turn yellow because they undergo a process called chlorosis, which is an aberrant yellowing of the leaves, due to the lack of chlorophyll. The main causes range from poor watering techniques, such as under or overwatering, suboptimal soil composition, nutrient deficiencies, (such as, potassium, nitrogen, magnesium and sulfur absences) to limited light exposure, pests (like spider mites) and some fungal diseases.

How do you fix yellow leaves on plants?

How often do you water night-blooming jasmine? Water and light

1- Under watering: The lack of water or not enough levels of water, will cause your night blooming jasmine leaves to turn yellow. Especially, at the end of the spring and summer time, where there is a lack of rain and there is too much dryness on the environment, the leaves of our night blooming jasmine will turn very crumbly, crunchy and with a deep yellow tone. If you were to rip off one of those leaves, and squeeze it, you would get a crunchy powder out of it, that is the sign of lack of water. The way we fix this is by increasing the watering regime for our night blooming jasmine plant. Cestrum nocturnum, before becoming well established, it requires thorough, weekly watering regime, however, if the weather is too hot, you will need to double check the soil in case it gets too dry and you will have to probably water it everyday to avoid your leaves to turn yellow and get dry.

2- Over watering: Excessive watering and the lack of proper draining system, especially, during the rainy season, the soil bed or your pot will fill up with too much water and won’t be able drain all the way. When this happens, the oxygen circulation process, is hampered in the soil and that prevents the night blooming plant from absorbing the required nutrients and also the rooting system will start rotting up developing wilt and other fungi. The way we fix this issue is by making sure that our pot has a hole at the bottom of it, so that the water can properly drain, as we know, our night blooming jasmine does not like a drenched and too wet soil. Also ensure that in those heavy rain days, simply move your plant to an area where there is a ceiling and can be protected from those heave precipitations. The same principle applies for an outdoors planted jasmine, you can cover it with some film, to create an umbrella sort of scenario which would protect our plant from getting drown.

An example of a pot that doesn’t drain the water properly and as a consequence, the leaves have turned yellow.
An example of a pot that doesn’t drain the water properly and as a consequence, the leaves have turned yellow.

3- Lack of light: If our plant is not getting enough light our night blooming jasmine plant leaves turn yellow. If there is not enough light hitting the leaves then rate of photosynthesis is very limited, impairing the growth of the plant. This is an easy fix, simply ensure the light is hitting semi directly our jasmine plant for about 5-6 hours a day and the situation should resolve within days.

Nutrient deficiency

1- Potassium (K) deficiency: Potassium is an essential macronutrient involved in all aspects of the plant growth and metabolism. it is also the main component involved in the responsiveness of the plant to behave in response to a stress factor/s, such as, pests, diseases, drought, etcetera. Potassium deficiency will first appear in the lowest leaves of our night blooming plant , in the form of bright yellow around the leaves margins. It first appears at the bottom of the jasmine plant due to the fact that potassium quickly and naturally moves from older to younger leaves. If potassium deficiency persists, these symptoms will progress to the middle of the plant, with the leaves first turning yellow at the tip but eventually, the entire foliage will turn yellow and the overall look of the plant will be stunned and stressed. The way we identify this issue is by regularly testing the soil for these nutrients and pH. We can help fixing this issue by purchasing easily available red salt powder or potash to add to our night blooming jasmine plant soil. The recipe is to use a half of a tablespoon to be dissolved in litre of water. The, shake it properly and pour it to the plant soil bed, once every week or every 10 days. An alternative to potash powder, is to use dried out banana peels. You can dry them out by leaving them under the sun for about 10 to 15 days and you can then make a powder out of them. Once you have this powder, dissolve a table spoon of it in a litre of water, then pour it over the night blooming jasmine plant once a week, until the issue is resolved.

An example of potash fertiliser supplement for K deficiency.
An example of potash fertiliser supplement for K deficiency.

2- Magnesium and sulfur deficiency: Magnesium is a micronutrient which is a key, central atom in the chlorophyll molecule. It works as the catalyst for the many enzymes involved in the plant growth process, stabilises the nucleic acids and contributes to the photosynthesis process. Sulfur is an essential atom involved in immobilising the chlorophyll molecule, it is involved in the protein synthesis of the plant and it is crucial in the fixation of another essential macronutrient like nitrogen. Usually, sulfur deficiency symptoms show on young leaves first appearing pale yellow and eventually delaying the growth and flower production of our night blooming jasmine plant. The way we fix this issue, is by adding Epsom salt, which is magnesium sulphate, to our foliage. This will help our night blooming jasmine to grow bushier, to grow more flowers, repel pest and will provide the vital nutrients. Follow the following protocol to fix the yellowing of the leaves due to magnesium and sulfur deficiency. Add one tablespoons of Epsom salt and mix it with one and a half litres of warm, not hot, water, and spray on the leaves once in a week. After you have sprayed the leaves thoroughly, but without drenching them, you can pour a little bit of that mixture directly to the soil as well, for an extra kick. After a couple of weeks applying this treatment, you will notice how the leaves come back to that lush green characteristic colour.

An example of magnesium sulphate fertiliser supplement for Mg deficiency.
An example of magnesium sulphate fertiliser supplement for Mg deficiency.

3- Nitrogen deficiency: Nitrogen is an essential macronutrient, component of the key structural, metabolic and genetic compounds in the plant. Nitrogen is also the crucial component of organic molecules, such as, chlorophyll, amino acids, proteins, nucleic acids, enzymes involved in all those important processes. Nitrogen is the nutrient which normally gives that healthy and vibrant green colour in our night blooming jasmine plant. When there is a lack of nitrogen, the leaves of our jasmine plant start turning yellow and our plant eventually dies off. This deficiency is commonly present, especially in the rainy season, when it rains a lot. Rain has a tendency to flush the nitrogen of the soil in a process called leaching. Nitrogen is a water soluble compound, that means, it dissolves and it is transported through or in the water. So, when there is a water flushed off the soil or out of our pot, that water can carry away that nitrogen of our plant. Often times, if you miss fertilising in the spring time (rainy season) with a nitrogen rich fertiliser, (it can be blood meal, fish emulsion, compost tea, worm castings), your plant will suffer from this leaching process and the result will be those leaves turning yellow and looking weak. The way we fix this issue is by feeding your plant, every three months and take good habit of doing it every spring or rainy season and your plant will not undergo these yellowing and deficiency process.

White nitrogen pearls to be used as fertiliser to cope with a nitrogen deficiency.
White nitrogen pearls to be used as fertiliser to cope with a nitrogen deficiency.

Soil composition

You have your plant beautifully green and it doesn’t turn yellow right away, but after about six to eight weeks, it slowly but progressively starts going downhill and turning yellow. That means, that the soil might not have the right composition and texture. If the soil is very sandy and the water can run through it very quickly, again the nitrogen can be flushed out with it and your plant will develop a nitrogen deficiency. The opposite is also true, if the soil is too compacted, it doesn’t contain a lot of sand but instead, it contains a lot of clay, then, that clay will hold on to too much moisture and the roots will rot and will not be able to absorb those nutrients either. When this happens, the bacteria in the soil, will start eating up those roots, deteriorating the rooting system and preventing the plant from up-taking the nutrients it needs. Another very common problem of having our night blooming jasmine planted in the wrong soil compositions is when, our soil has a lot of bark and mulchy material. Those big pieces of bark which haven’t been broken down yet coming from wood compost can get buried out in the soil, and a process called nitrogen sequestration take place. Bacteria found in the soil, will use the nitrogen (from the soil), that your plant will use as food, to break down the carbon from those big mulch pieces, preventing the plant from up-taking the nitrogen they need. We can fix these issues by adding some finished compost, as it contains a lot of humus ( finished broken down organic material) if the soil is very sandy and that is going to allow the soil to hold on to nutrients like a sponge. On the other hand, if the soil is too high in clay, you could add a bit of sand, however, bear in mind, that this is not my preferred method, as if you add too much sand the mixture can result in concrete! making your soil even harder. We can add compost instead, allowing the clay to break up, that way the clay will be providing the minerals for your plant and the finished compost, will break up the rest of the materials allowing the soil to drain up properly.

Big pieces of mulch that need to be broken down to be finished compost and shouldn’t be buried.
Big pieces of mulch that need to be broken down to be finished compost and shouldn’t be buried.

Transplant shock

It is really common situation that we have just put our plant on the ground, that started beautiful and green, but the moment you plant it on the new soil bed in your garden or pot, their leaves start turning yellow. This might be because the plant might need about two weeks to accustom to the new soil and usually they turn green back again. This is a phenomenon called transplant shock. That can because of a change in pH, a change in soil texture, soil moisture, soil temperature, and a wide range of different variants that can lead to this problem in the leaves of our night blooming jasmine. All these variants will make the plant shut down temporarily, preventing it from up-taking nutrients and making it overall, stressed, for which those leaves may start looking a bit stunned and yellow.

Am example of a transplant show and all the leaves in the plant have turned yellow.
Am example of a transplant show and all the leaves in the plant have turned yellow.

Natural life cycle

Sometimes at the end of the flowering season, the plant changes its priorities, in terms of the processes that the jasmine plant needs to focus on. Nitrogen is not being prioritised for foliage or leaves production anymore, instead, it is prioritising flowering bud production or it is recharging those growth hormones for the following season. So, you might experience some yellowing of those leaves, this is not bad, it’s just normal stage at the end of the cycle. The important thing is, to check for spots on those leaves, excessive dryness and all the above mentioned points that responds to a lack of watering or nutrient up-take.

Infestation of spider mites

Having your night blooming jasmine plant infested with spider mites is another common way to get its leaves yellow and eventually, they destroy the plant if left untreated. Spider mites feed on the sap of the plant through piercing and sucking the “juice” off the underside of the leaves. When this happens, a small wound is created in the surface of the leave in the form of yellow spots giving the leaves a spotty appearance. If the feeding becomes more severe and the burden of mites increases, eventually the leaves of our night blooming jasmine will look really yellow to bronze tone, compromising the integrity if the plant. It becomes crucial that we treat our plant. The way we ensure this issues is fixed is by practising good watering and fertilising techniques, providing our jasmine plant with the proper water regime and optimal feed, as mites thrive in plants under stress. Make sure to physically remove the mites and their webs from the plant by using a high-pressure water spray or hose. Use insecticidal soap and horticultural oil to make sure the leaves taste” nasty” to them in a way that they can feed on them and also it will kill the mites in direct contact with these chemicals.You can also make use of natural predators, such as, lady beetles, which naturally control spider mites populations. Lastly, if the infestation is quite severe, ensure you use long-lasting insecticides (containing bifenthrin and permethrin), once every fortnight until the issue is resolved.

Jasmine leaves turning yellow due to a severe infestation of two spotted spider mites
Jasmine leaves turning yellow due to a severe infestation of two spotted spider mites

There you go! Paying attention to all those points described above will help us ensure, that our night blooming jasmine is getting all the nutrient, water, light and soil requirements to prevent its leaves to look sad and yellow, in a way that we will be able to preserve their enticing green foliage and overall health of our night blooming jasmine.

This article was published with these tags attached:

gardening flowers yellow leaves treatment
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