Oleander has yellow leaves and these fall off

The dilemma begins with individual, yellowed leaves. If these first signs of a problem with the oleander are underestimated, over time all the leaves will turn yellow and fall off. Since various causes can cause this type of damage, there is no ready-made answer to the question. By putting all the general conditions of cultivation to the test, the true cause of yellow leaves on rose laurel ultimately emerges. Find out what to do to get your suffering oleander back on track here.

Cause: drought stress

What to do: water properly

The water needs of an oleander cannot be overstated. The magnificent flowering shrubs are so thirsty, especially in summer, that the saucer should be permanently filled with water. Your rose laurel reacts to drought stress with yellow leaves within a short time. Once all the nutrients contained in it have been transferred to the roots, the shrub sheds the leaves to reduce the degree of evaporation. Instead of watering an oleander on a strict schedule, please switch the water supply to this immediately:

• Dip a dried root ball in water until no more air bubbles rise
• During the warm season, place the tub in a tall saucer filled with water
• Always water the substrate when it has dried
• Refill evaporated water in the coaster promptly
• Never water the rose laurel in direct sunlight

Although the oleander comes from the Mediterranean region, it requires calcareous water. Please only use normal tap water at normal room temperature. Daily gardening practice has shown that soft rainwater causes a lack of lime, after which the leaves turn yellow.

Cause: nutrient deficiency

What to do: fertilize in a balanced way

If the yellow leaves in the oleander spread out evenly, this indicates a nutrient deficiency. This applies in particular if the damage occurs in the middle of the summer growth and flowering period. Please consider that a rose laurel is one of the most consuming plants. Therefore, check the nutrient balance to switch it to these intervals if necessary:

• Fertilize weekly from May to August
• Apply an NPK fertilizer with 15-10-15 or higher
• Ideally add to the irrigation water as a liquid fertilizer
• Water before and after with clear water

The rest of the year, stop feeding. Outside of the flowering period, your oleander does not need any additional fertilizer. On the contrary, this could lead to over-fertilization, which in turn causes the leaves to yellow and fall off.

Cause: old age

What to do: Cut back or taper off

As an evergreen flowering shrub, an oleander does not shed its foliage in autumn and winter. However, this characteristic does not mean that the individual leaves live forever. In fact, an oleander leaf lives for about 2 years. At the end of its life, it gives up its remaining nutrients to the shrub, turns yellow and falls to the ground. In the long run, this natural process leads to an aging from below. The young leaves above it no longer let enough light through, so that shed leaves are not renewed at the base. If you can identify this process as the cause, cutting back will fix the problem. How to do it right:

• Thin out an oleander thoroughly at least once a year
• Cut off deadwood and shoots that are too close together at the base
• Shorten branches that are too long by up to three thirds
• Make the cut just above a leaf base

If the annual shape and maintenance cut has been missed for several years, so many yellow leaves have fallen that the bare leaves are far advanced. Thanks to a robust pruning tolerance, you can rejuvenate your oleander. The pruning can be done up to a shoot height of 10 cm. The shrub quickly sprouts from the old wood, so that it regenerates within 1 to 2 years.

Cause: Wrong location

What to do: Relocate immediately

As a Mediterranean plant, oleander loves the sun and is not winter hardy. This has the advantage that the opulent flowering shrub can cause a sensation on the balcony and terrace from spring to autumn. If he does not like the assigned location, the rose laurel reacts with yellow leaves that fall off sooner or later. Since the frost-sensitive plant depends on cultivation in a bucket, you can optimize the location if in doubt. The damage regenerates quickly under the following conditions:

• Relocate to a full sun, warm spot
• Protection from wind and rain is recommended
• Gladly on the south side of the house

Often leaves with yellow spots develop immediately after clearing. This damage occurs when an oleander is left in full sun continuously and suffers sunburn. As a sure sign of this cause, the yellow spots stop spreading. By allowing a rose laurel to acclimate for 1 to 2 weeks in a semi-shady location, you effectively prevent such leaf damage. Affected leaves should not be removed as the remaining green tissue continues to participate in vital photosynthesis.

Cause: Improper winter storage

What to do: Overwinter in a way that is appropriate to the species

An oleander is robust enough to stay outdoors in mild winter locations. This applies, for example, to the Rhineland or the wine-growing regions. As long as the thermometer does not drop below -5 degrees Celsius at night, no special precautions are necessary. Where it gets rougher in winter, on the other hand, there is a risk of yellowing and leaf shedding if a rose laurel is not properly guided through the cold season. Therefore, question the hibernation in order to create the following ideal conditions:

• Put the oleander in a light-flooded winter quarters
• Gladly in the unheated conservatory, the bright stairwell or the sunny garage
• Compensate for a deficit of light with plant lamps
• Temperatures between 0 and 10 degrees Celsius are optimal
• The darker the room, the lower the temperatures should be
• Water less without letting the root ball dry out
• Don't give fertilizer

Lack of light, too low and too high temperatures cause your rose laurel to retract and shed the leaves. After you have optimized the conditions, the shrub will recover over the following weeks and months. If no better winter quarters are available, this is no reason to worry. At the latest when you clear out your oleander in spring, new, lush green leaves will sprout.

Cause: root pressure

What to do: repot

When you are young, your oleander will grow so quickly that the tub will be fully rooted within a year. If the ornamental shrub is not repotted in a larger container with fresh soil, the resulting root pressure will affect the supply of the leaves. These turn yellow and fall off, although it is regularly watered and fertilized. If the root strands grow out of the bottom opening and press up through the substrate, repot the constricted rose laurel like this:

• The best time is in early spring, just before clearing out
• The new bucket is no more than 5 to 10 cm larger in diameter
• Fill the container one-third full with a mix of potting soil, clay and sand
• Tie the shoots together with string and repot the oleander
• Clean off any yellow leaves
• Shake off or spray off the used soil
• Cut out soggy roots

If you want to use the previous pot again, you can shorten the roots by 2 to 3 cm. Plant the rose laurel in such a way that the previous depth is maintained. Pour generously. So that the stressed shrub can recover, it stays in a partially shaded, sheltered place for 8 to 10 days.

Cause: oleander canker

What to do: Fight naturally

If you were able to rule out all the causes mentioned so far, there is reason to assume that the plant is suffering from oleander canker. In addition to the yellow, falling leaves, the shoots are also covered with gray-brown to black growths. Above these growths, the branch dies, which is the reason for the yellowing and shedding of the leaves. Oleander canker is caused by a bacterium. Experts assume that all European oleanders are infected with it. Whether the disease actually breaks out depends on the constitution and resistance of the respective plant. This is what to do now:

• Cut back all affected shoots down to the healthy wood
• Dispose of the infected clippings in the household waste
• From now on, pay attention to optimal care in order to strengthen the resistance

Scientific observations have shown that a vital and strong oleander can live with the infection. The more vigorous the shrub, the faster it will close the gaps with fresh shoots and young leaves.

Cause: All kinds of lice

What to do: Fight with home remedies

The succulent, evergreen leaves are a favorite target of all species of lice. Aphids, scale insects, mealybugs and mealybugs have no scruples about settling on the leaves. The pests pierce the tissue with their mouthparts and extract the plant sap from the leaves. As a visible symptom, the leaves discolour, often curl up and fall off. How to deal with the plague with home remedies:

• Quarantine the affected oleander
• Remove any leaves infested with pests
• Rinse the shrub – upside down if possible
• Wipe leaves and shoots with an alcohol-soaked cloth

As a natural control agent, the classic soft soap solution puts an end to infamous lice. Put 1 liter of lime-free water and 1 tablespoon each of soft soap and alcohol in a spray bottle. Treat the upper and lower sides of the leaves with this spray every 2 to 3 days to destroy even the last lice.

Conclusion

If your oleander has yellow leaves and they fall off, a variety of triggers can cause the damage. Therefore, subject the entire cultivation to a precise analysis. The spectrum of possible causes extends from drought stress, lack of nutrients and senescence a wrong location and improper overwintering up to root pressure, oleander cancer and pests. Once you have found the actual cause, your troubled oleander will recover as a result of adequate measures. These instructions not only show possible causes, but also explain what needs to be done.

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