Since most oleander varieties do not have sufficient winter hardiness, the Mediterranean plant is usually cultivated as a container plant in our latitudes. In order to be able to grow healthy and vigorous even under these difficult growing conditions, a few important rules must be observed. One of the most important factors here is repotting the container plant. Because so that the oleander has enough space to spread its roots, it is necessary to provide it with fresh soil and a larger pot from time to time. This is the only way to guarantee that the roots can continue to absorb sufficient water and nutrients.
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time
Spring is a good time to provide the oleander with fresh soil. Young plants need to be repotted at least once a year. With older, fully grown plants, this is only necessary at greater intervals. In April to May, the buckets that were hibernated in a frost-free winter quarters can be put back into the open air. With a new, larger pot and fresh soil, the plants start the new growing season much better. Therefore, you should repot the oleander again beforehand. If necessary, repotting is also possible all year round.
Ideal planters
The roots of the oleander grow in width rather than in depth. That is why the ideal planter is a little wider than it is deep. When repotting, it is best to choose a container that is only slightly larger than the old one. This has the disadvantage that young plants may have to be repotted twice a year, but in this case the root ball is more evenly rooted. Wide vessels also offer more stability than slim, tall variants. Buckets that offer the root ball about two to three centimeters more space on each side and have drainage holes in the bottom area are perfect.
Substrate
A classic, humus-rich potting soil is not suitable for an oleander. It is better off in a loamy, structurally stable substrate with a moderate proportion of humus. Experts mix their own oleander soil in order to imitate the soil conditions at the natural location of the oleander as precisely as possible.
- 5 parts of commercial potted plant soil
- 1 part clay
- a handful of garden lime (for all lime-loving oleander species)
Young plants
Oleander grows very quickly, especially at a young age. Therefore it has to be repotted at least once a year, sometimes more often. How often this is actually necessary depends on the pot size and the plant. At some point the growth slows down and the oleander enters the flowering phase. There are also varietal differences in growth. The varieties of oleander that grow red or pink, simple flowers grow the strongest. On the other hand, yellow-flowered varieties, especially when the flowers are double, grow the weakest. These varieties remain significantly smaller than the red varieties even with age.
Instructions for repotting
Oleanders should be checked at least once a year in spring to see if they need a larger pot. Fresh earth doesn’t do any harm.
Step 1: Checking the root ball
Grasp the plant as far below as possible just above ground level and carefully pull it out of the planter. If you pull on the young shoots, they will tear off very quickly. If the fine, light brown roots can already be seen on the outside of the root ball, it is time for a larger pot. Be sure to also check the bottom of the ball, there is often a fine, dense network here. This is a sign that the plant is suffering from a lack of space. In this case, the new pot must not only have a larger diameter, but also more leeway in height.
Tip : If the root ball does not slide easily out of the pot, check whether roots have already grown out of the drainage opening in the soil. If the pot cannot be destroyed, you have no choice but to cut off these roots.
Step 2: remove old soil
First, carefully loosen the roots a little. Try to remove as much of the old (used) substrate without unduly damaging the roots. This leaves more space for fresh soil, which the oleander urgently needs.
Step 3: tear open the root ball
If a dense, centimeter-thick network of roots has formed on the bottom of the pot, you can tear it open a little. This allows the new roots to spread better in the fresh soil.
Step 4: Select a new vessel
Since the oleander grows very quickly at a young age and the roots spread to the same extent, the new planter should be about two to three centimeters larger than the old pot. Vessels made of clay (terracotta) are particularly suitable for cultivating oleanders, as the material better balances the water balance. However, above a certain size, the bucket becomes very heavy. Therefore, it should be considered whether a plastic pot could be of better use as an alternative.
Step 5: create drainage
Drainage in the planter is also important. The bigger the pot, the more difficult it is to calculate how much water the plant needs. In one case or another, the oleander gets wet feet – a condition that the plant cannot survive in the long run. The bottom layer (around 10% of the height of the pot) is suitable:
- Blähton
- Kiesel
- Broken bricks
- coarse lava granules
Tip : Place a weed or garden fleece on top of the drainage. This way, the drainage layer is not clogged by washed out soil or the roots of the oleander.
Step 6: check potting depth
If you are placing the plant in a larger pot, check that the planting depth is correct after filling in the drainage. To do this, first insert the root ball into the new pot. The surface of the ball should be about two to three centimeters below the edge of the pot. If the root ball is too deep, first put enough substrate on the drainage system until this depth is reached. If the Nerium oleander is too high, the irrigation water runs over the edge.
Step 7: fill in the substrate
If you use a special plant substrate for your oleander, it will definitely pay off. Only with the right soil can the plant thrive, form numerous flowers and be protected from diseases. It is therefore worthwhile to buy high-quality professional soil for the plant or, alternatively, to mix a substrate yourself. Now gradually fill the remaining gap between the root ball and the container with soil. Keep pressing it firmly so that no cavities are created.
Step 8: fertilize
It is best to mix a little slow-release fertilizer right into the fresh substrate. Buy container plant fertilizers specially formulated for oleanders or Mediterranean plants. A slow release fertilizer does not completely replace normal, regular fertilization, but it does create a good basis. These fertilizers consist of a combination of mineral and organic fertilizers and provide the plant with important nutrients from day one. Long-term fertilizers usually work for about six months and, in addition to the main nutrients, also contain important trace elements.
Step 9: casting on
In order to sludge the earth well and to remove any cavities, pour the oleander vigorously once after repotting.
Step 10: maintenance cut
At the end, the repotted oleander gets a maintenance cut. All sick, old and light shoots (long, thin shoots with large leaf spacing) must be removed.
Adult plants
If the oleander has reached its final size or if a larger pot is no longer possible, you still have to “repot” it. Only the roots are cut and fresh soil is poured in. Then the plant comes back into the old, cleaned planter. Boldly cut off at least two to three centimeters of the roots at the edge of the ball with a sharp, clean knife. Then lay the oleander on its side and repeat the procedure on the floor.
You can then easily loosen the root ball with your hands by pulling it apart a little. Remove as much of the old substrate as possible. At the same time, watch out for rotten or dead roots. These must also be removed with a smooth cut so that diseases such as root rot cannot spread. Then fill in lightly fertilized, high-quality oleander substrate. At the same time, around 10 to 20% of the overaged shoots should be removed.
Tips for repotting very large plants
Repotting very large plants is not that easy. The size and weight of the ball alone cause a number of problems. That’s why it’s important to keep a few tips in mind that will make repotting easier.
Tip 1: get help
Repotting very large potted plants with two people is better than repotting alone. It is best to organize a strong helper who can help you. Depending on the weight of the plant and the strength of the gardener, different strategies can be used to get the oleander out of the bucket. It is easiest if one person holds the pot and the other grabs the oleander far below the trunk and pulls it out. It is more back-friendly if the pot is tilted on its side beforehand.
Tip 2: water
Water the oleander about an hour before you plan to repot. If the root ball is damp (not wet!), It is easier to remove it from the bucket.
Tip 3: tie it together
Very large specimens of the Nerium oleander should first be loosely tied together with a rope or tension belt. This means that the shoots are not in the way when repotting and the risk of accidentally damaging the shoots is minimized.
Tip 4: check the vent hole
Check in advance whether any thick roots are growing out of the drainage hole in the soil. You should cut this off before pulling out the root ball. Do not tear at it, because the roots are often woody and therefore very resistant. A smooth cut with a knife will do less damage to the plant.
Tip 5: remove the balls from the pot
Sometimes the pad seems to have grown into the pot and cannot be removed. In this case, simply run an old bread knife between the pot and the root ball to separate the overgrown roots from the pot. This problem usually occurs with clay pots.
After repotting
After repotting, put the oleander in a slightly higher coaster. The plant has an enormous demand for water in the warm summer months. She has no problem with it when the pot is about a third in the water. The oleander will soak up the water completely for the next few hours.
Conclusion
The necessary care measures for the oleander also include regular repotting. While young plants often have to be repotted several times a year, older plants only need to do this at longer intervals. If a larger pot is no longer possible, a root cut is made so that the plant can be supplied with fresh soil again.
