Magnolia gets yellow leaves: what to do?

The ornament of a magnolia tree are the large, pink flowers in spring. The green leaves that sprout a little later, on the other hand, are inconspicuous companions. In autumn they turn yellow and separate from the tree. However, the yellowing must not happen at an earlier point in time! It doesn't take long to look for the cause. Usually a lack of nutrients is responsible for this. But the magnolia can recover again.

Pay attention to the timing of the discoloration

The fall of leaves in autumn is not entirely correct, because both evergreen magnolias and deciduous varieties are cultivated in this country. The evergreen specimens are planted in mild regions of the country or in pots because they are sensitive to frost. They keep their foliage dressing all year round. Excessive yellow leaves are therefore a cause for concern, regardless of the season. In the case of deciduous varieties, yellow leaves are only safe in autumn. In summer or even spring they are a sign that something is wrong with the tree.

Plant disease chlorosis

Yellow leaves on magnolia are symptoms of a plant disease called chlorosis. It is also known as jaundice or bleaching among gardeners. Photosynthesis in the leaves of the plant is disturbed. New chlorophyll cannot be formed; existing chlorophyll is broken down. But chlorophyll is the substance that gives the leaves their deep green color. The less of it there is in them, the more yellow they become. The yellowing of the leaves is not the only consequence of chlorosis. If you cannot find a solution to the causes of this disease, the following effects will be added:

• Leaf shedding
• poor stature
• growth comes to a standstill
• eventually the plant dies

Chlorosis triggers

In order to stop magnolia from suffering, you need to know what caused the chlorosis. Fortunately, it's not a difficult fungal disease to fight, just a nutritional deficiency. In most cases the magnolia lacks iron (Fe) when the leaves turn yellow, but occasionally the supply of magnesium (Mg) can also be insufficient. Both elements are essential for the formation of chlorophyll.

Lean soil

It is possible that the roots of the magnolia tree find insufficient amounts of these two nutrients in the soil. This is particularly likely even if it was given the optimal location when it was planted. This tree prefers acidic and firm soils. What its owner must know, however, is that such soil is poor in iron and magnesium. If the poor soil meets insufficient fertilization, it can quickly lead to an undetected undersupply. The correct interpretation of the yellow tint can ultimately open the eyes and pave the way to the solution.

Tip: Water the lime-sensitive plant with soft rainwater to keep the pH in the preferred low range of 5.5 to 6.8. This enables this tree to have a good uptake of nutrients.

Compacted soil

Sometimes it can also happen that both elements are present in sufficient quantities in the soil and yellow leaves still appear on the magnolia. Then the nutrient uptake will probably be disturbed. Compacted soil inhibits root growth and also makes it more difficult for the soil to take root. In addition, compacted soil tends to become waterlogged, which can also damage the roots. But only intact roots can absorb enough nutrients from the soil.

Wrong fertilizer

Even if the soil itself is not poor in nutrients, it still has to be supplied with new nutrients every now and then in order to compensate for the consumption of the magnolia. But not all fertilizers are created equal. If you purchase magnolia fertilizer from retailers, it is high time you read the fine print on the packaging. What is the proportion of iron and magnesium? Many fertilizers contain only modest doses of these two elements or leave them out at all.

Countermeasures

Ultimately, it is not unlikely that there is a combination of two or all three causes. The easiest way to see compacted soil and the nutritional composition of a fertilizer is by looking closely. The nutrient content of the soil is not readily apparent. But you have the option of having an inexpensive soil analysis carried out. To do this, you need to send soil samples to an analytical laboratory and wait a few days for the result. Below are steps you can take to combat chlorosis.

Loosen the soil

Before you reach for the fertilizer, you should first loosen the soil. If the soil is too compact, it can be tedious. Nevertheless, care must be taken not to damage the root system. The magnolia is namely shallow root. Their roots do not reach deep into the earth, but are close to the surface of the earth. Do not stay close to the trunk, but loosen up the entire area below the crown.

Fertilize the soil

Based on the severity of the symptoms of the disease and the values ​​of the soil analysis, the ideal fertilizer or Dosage can be selected. If the leaf color is not yet advanced, it may be sufficient to work in plenty of humus and compost after the soil has loosened. If necessary, you can then supply the plant with a fertilizer containing iron and magnesium.

Note: If the magnesium deficiency is very pronounced, the solution is to immediately supply it Epsom salt at.

Prevent chlorosis

So that the chlorosis does not strike again, the iron and magnesium values ​​must remain in the green area in the future. On the other hand, it is also not allowed to fertilize generously, because overfertilization is not good for this plant either. A magnolia will be satisfied when it has rotted compost in the spring and fall. Only tub specimens require a more extensive supply of nutrients. If you fertilize with a commercially available fertilizer, it must contain iron and magnesium. In addition, there should only be extra portions of iron and magnesium as soon as the magnolia tree begins to change its leaf color unexpectedly towards yellow.

Tip: Fertilize the magnolia with one Rhododendron fertilizer. Both plants have similar demands on the soil. They like it sour and loathe lime.