Basically, the Dipladenia is a very easy-care plant. Nevertheless, it happens again and again that the leaves turn yellow or get brown spots. The potential reasons for such a development are manifold. If you can find a quick diagnosis and react quickly, you can usually save your plant. In order to avoid confusion of terms from the outset, it should be noted that Dipladenia and Mandevilla are two names for one and the same plant genus from South America.
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General information about the yellow coloration of the Dipladenia leaves
The yellow color of the leaves is the most common disease symptom of the beautiful plant. Conveniently, it is also easily recognizable for the hobby gardener, so that he can take measures to cure the Dipladenia if necessary.
Below are the possible causes of yellow Dipladenia leaves in more detail.
Potential causes
In principle, there are five possible reasons for the yellowing of the leaves:
- Age of the leaves
- too little light
- too much water
- too few nutrients
- Pest infestation *
* The pest infestation can ultimately also promote brown spots. This point will therefore only be discussed in more detail at the very end of the article.
Age of the leaves
It doesn’t always have to be a real problem that yellow leaves bring with it. In fact, old Dipladenia leaves also take on the color, gradually harden and fall off. As with all evergreen, Mediterranean and exotic plants, the Dipladenia also has a regular exchange of leaves.
The symptom only becomes a problem when a large number of leaves are affected by the yellowing. Then it is important to continue to see what could be the cause. In this context, it makes sense to break down the possible causes by season:
- Reasons for yellow leaves in summer
- Reasons for yellow leaves in winter
Yellow leaves in summer – causes and solutions
Yellow leaves in summer can be caused by:
Too shady, cool location
The Dipladenia is an extremely sun-hungry plant. It only thrives and blooms when it gets enough sun and warmth. If it is too much in the shade and cooling for a long time, it becomes sick, which favors the yellowing of the leaves.
Important:
- place outside
- location in full sun
Excessive wetness
Is the plant set up appropriately and still get yellow leaves? Then the cause may be excessive moisture. If the Dipladenia is poured too often and / or too heavily, waterlogging occurs. This goes hand in hand with an impairment of the root function. As a result, the roots can no longer supply the leaves properly. The latter turn yellow and fall off.
But what exactly does “moderately moist” mean? The plant should only get water when the upper half of the soil layer has dried out. To determine the status, you can use your own finger or – if you want to keep it more professional – with a moisture meter from a specialist retailer.
If you find out during the test that the soil is very wet, you have no choice but to repot the Dipladenia as quickly as possible:Step 1: Cover the bottom of a new pot with nutrient-rich potting soil.
Step 2: Carefully take the Dipladenia out of the old pot and remove all extremely wet and rotten parts. Care should be taken to remove as little as possible. Otherwise, the plant can suffer so badly that it will soon die.
Step 3: Now put the bale of the Dipladenia in the new pot.
4th step: Fill the pot with the potting soil and press it down firmly.
5th step: water the soil lightly. After spontaneous repotting in summer, you have to expect that the above-ground growth of the plant will slow down a little. She is now busy with rooting.
Too few / wrong nutrients
Does the thumb test show that everything is OK in terms of water technology? Then the cause is probably too few or wrong nutrients. The Dipladenia needs a relatively large amount of nutrients – for this it rewards the hobby gardener with a wonderful display of flowers. If the earth is used up and is not replenished in a timely manner, there is a nutrient deficiency. This is first shown by the leaves, which take on a yellowish color. You have to fertilize the plant regularly in summer with a suitable container plant fertilizer to ensure an optimal supply of nutrients.
Properties of the right container plant fertilizer:
- Nitrogen, phosphate, potassium compounds in the ratio 15%, 10%, 15%
- Trace elements such as magnesium, copper, iron, zinc, boron, manganese, molybdenum
You should fertilize from April to August. During this period, simply apply the container plant fertilizer whenever the plant needs water.
Yellow leaves in winter – causes and solutions
The Dipladenia is not hardy, so it must not be outside in the cool season, but needs adequate winter quarters. However, problems often arise in this context. If the plant spends the winter under unfavorable conditions, the leaves turn yellow and fall off.
Potential problems in winter quarters:
- light mangle
- severe cold
In order to overwinter the Dipladenia well and healthily, a frost-free area with sufficient light is essential.
Important features of the winter quarters:
- Temperatures from 10 ° C to 15 ° C
- bright place (very close to the window) *
* This point should be taken very seriously. Every centimeter more distance to the window costs the plant light and thus energy. This can result in yellow leaves. The sunshine, which is already sparse in winter, falls directly on the Dipladenia at best. Other plants (such as trees) that partially or completely block the sun outside are just as disadvantageous as drawn curtains in the interior.
Incidentally, the loss of individual leaves can be tolerated as long as the plant still has many green leaves and tendrils.
What else to watch out for in winter:
- far less water is needed than in summer
- Water moderately every one to two months
- perform the finger test again
General note
Whether in summer or winter: if yellow leaves appear and fall, the plant must never be given more water (unless excessive drought is the cause …). Especially with waterlogging, ignorant, panicked behavior would be absolutely counterproductive. Therefore, it is better to first clarify exactly what is really going on.
Brown spots on the leaves of the Dipladenia
Brownish spots on the leaves and / or shoots of Dipladenia can theoretically have the same causes as yellowing of the leaves, but sometimes the problem is due to something else: so-called Rhizoctonia disease or fungal soft rot.
In both cases there is usually no rescue and the infected Dipladenia has to be thrown away. It is also important to spray nearby, healthy plants with a suitable fungicide as a precaution.
Another cause can be leaf or stem rot of Dipladenia. Round, slightly deepened spots appear on the leaves, which are first brown and then gray in color. On the underside, ring-shaped fungal spores accumulate within the leaf spots.
Both leaf or stem rot and mold can be cured with suitable spray fungicides.
Pests in Dipladenia as a possible cause
Basically, pests are rather rare in Dipladenia. This is because the sap is toxic. There are therefore only a few insects who dare to approach the beauty. The enemies of the plant include:
- Scale insects
- Mealybug
- Spider mites
These do not directly cause yellow or brown discoloration, but can affect the Dipladenia to such an extent that their health suffers and this leads to the symptoms.
