The orange tree is a very pretty tree, especially when it produces its small, fragrant white flowers. But if there is something that worries all of us who have at least one specimen, it is the fact that sometimes, and perhaps for no apparent reason, its leaves turn yellow. And it’s clear, a plant that has yellow foliage is a plant that has trouble.
Why can the orange tree have yellow leaves? Can we do anything to prevent his condition from getting worse? We talk about it below.
The soil lacks certain nutrients available to the plant
The orange tree, and indeed all citrus fruits, are trees that when planted, for example, in clay soil, they tend to show symptoms of chlorosis, such as leaf yellowing. Indeed, although these soils can be very nutritious and fertile, for the simple fact of being alkaline (and therefore having a very high pH, 7-8), certain nutrients are blocked and therefore inaccessible to the roots. .
Chlorosis: an easily preventable disease
Therefore, it is not uncommon for our tree to have yellow leaves if it grows in this type of soil, because in these conditions it lacks iron and manganese, both essential for the plant to be able to manufacture chlorophyll on the one hand, and to carry out photosynthesis on the other. So how do we know if you really have this problem?
We said the leaves turn yellow, but… how? well the loss of its natural green color begins from the edge of the leaf inwards. In the specific case of iron chlorosis or lack of iron, we will also see that the nerve remains green. What can we do?
Although this can be quite a serious and serious problem, the solution is not too complicated. In reality, To prevent it from getting worse, we will only have to pay it with citrus fertilizer, which contains all the nutrients you need and, above all, they are available for you to absorb from the moment you compost. But yes, it is very important that the instructions for use are followed so as not to add more fertilizer than indicated.
But beware: this will not be enough. If we irrigate with alkaline water, it will have chlorosis again. Therefore, it is necessary that where possible, rainwater is used for irrigationor sweet, suitable for human consumption.
The frequency of irrigation is not adequate
Either because it is watered more than necessary, or because on the contrary it is not watered enough, the orange tree can end up with yellow leaves. But the reality is that it is difficult to control irrigation, because the frequency must be variable according to the change of seasonand the variations that occur in temperature, wind, rain, etc., throughout the year.
Watering is particularly necessary -and I would say urgent- during a heat wave, and even more so if the thermometer reaches values of 40ºC or something higher for several days in a row. But we also cannot neglect it if the land in which it grows dries out quickly, otherwise the roots will suffer significant damage. For this reason, You will need to water more often in summer than in winter.. The question is: how many times a week would be correct?
The truth is that this is a question that does not have a single answer, since we do not have the same climate in La Coruña as in Badajoz, for example. Even within the same province, there are different microclimates. I can say myself that, in the extreme south of the island of Majorca, where I live, it rains much less than in the Sierra de Tramuntana (which is to the northwest); In fact, we are talking about a brutal difference: in my city about 350mm of precipitation falls annually, but on the other hand in the mountains about 1000-1500mm falls. And of course my orange tree needs much more watering than the fruit trees in the northwest of Mallorca.
Next, to know when to water it, it is important to know -in the broadest sense- the climate of the region where it is grown, since in this way we can have an idea of when to water it. But if you have any doubts, I recommend checking the soil moisture. This is something you can do with a simple wooden stick: just insert it all the way in, and that’s it. When you take it out you will see if it is wet or not: in the first case, you will see that a little earth has stuck to it; and in the second, on the contrary, it will come out practically clean and dry.
Symptoms of excess and lack of water in the orange tree
But how do we know if we’ve overwatered it? What symptoms will he show? Good, Well, a drowning orange treeeither because it has been watered a lot, and/or because the soil is so compact and heavy that it does not let the air circulate well between its pores -which happens in poorly drained soils-, You will see the leaves turn yellow starting with the lower ones and continuing to the newer ones.
How do you know if the drainage is good or bad?
If the exact opposite is happening, i.e. it is watered too little, the first leaves to turn yellow will be the new ones. These will eventually dry out and fall off. In addition, the ground will look very dry and may even crack.
How to save it? well if there is excess water, what we will do is suspend the water for a while, until the earth dries up. Likewise, we will have to treat it with a systemic fungicide like this so that the fungi do not damage it.
If it is in very compact, poorly drained soil, if possible (for example, if we planted it a year or less ago, or if it is a young tree), it is better to remove it, make a hole of at least 1 x 1 meter, and fill it with a mixture of peat and perlite in equal parts.
Yes if what happens is that it dries out, we water it more often. In addition, it is important to pour water until the soil is well soaked, otherwise the tree will not be able to quench its thirst.
The orange tree has parasites
Although it is a fairly easy tree to care for, it must also be said that it usually has the weird problem of pests, especially during the summer. The most common are scale insects, aphids and thrips, all insects that feed on leaf sap. (and the aphid also from that of the flowers), and that in doing so they leave discolored spots. If the situation persists, the leaves eventually turn yellow, dry out and eventually fall off.
What to do? The best is to prevent, and for that I recommend treating the tree before symptoms appear with diatomaceous earth (available here). The leaves are wetted with water, then this product is poured over them. Naturally, it does not harm the environment, except of course for those small pathogenic insects.
But if there are already symptoms, the ideal is to use an insecticide, following the instructions for use. If you opt for a spray, like this one, you will spray the product on both sides of the leaves, the branches, and it is also advisable to do it on the trunk.
As you have seen, there are several reasons why the orange tree may have yellow leaves.