The oleander (Nerium oleander) is one of the heavy feeders and therefore has an exceptionally high nutrient requirement - rather a rarity in Mediterranean plants, which are mostly used to poor soil. However, the oleander naturally thrives on frequently flooded riverbanks, where they are plentifully supplied with alluvial nutrients. Therefore, you should not only water the oleander frequently, but also fertilize it at least once a week.

Oleander is very nutrient hungry

Fertilize oleanders during the growing season

During the winter months, the oleander has to be watered, but not fertilized: the evergreen plant needs a break in the cold season and should therefore be overwintered as coolly as possible. Start regular fertilization at the beginning of the growing season in March and continue until mid-August, but no later than the end of August. After that, the oleander should no longer be supplied with nutrients so that the shoots can mature in time before the winter break - this gives the plant, which is only winter-hardy to about minus five degrees Celsius, a certain protection from cold temperatures. After all, oleanders should be cleared into winter quarters as late as possible.

Potassium fertilizers and lime are also good for oleanders

You can also increase winter hardiness by providing the oleander with potash fertilizer between mid and late August. This supports the shoots in maturing in time, but must not be used later than specified. Otherwise it can no longer develop its effectiveness. An additional dose of potash fertilizer as well as fertilizer lime at the beginning of the growth period is also useful in spring, especially if you fertilize with long-term fertilizer.

Which fertilizer is suitable for oleanders?

Oleander can be effectively supplied with a variety of fertilizers and tolerates both mineral and organic matter very well.

For the forgetful: slow-release fertilizer lasts a long time

If you are forgetful or just want to be on the safe side, give your oleander a long-term fertilizer for flowering plants at the beginning of the growing season. Various remedies are available on the market that cover three, four, six or even twelve months. Fertilize the oleander at the beginning of the season and carefully work the fertilizer into the substrate. You then have rest for the specified period, and over-fertilization is also difficult - due to the very slow release of nutrients. Even after or during repotting, the oleander should be supplied with a long-term fertilizer.

Weekly fertilizer for flowering plants or oleanders

Alternatively, fertilization with a mineral flowering plant fertilizer or a special oleander fertilizer is of course also possible, but this should be carried out once or twice a week, depending on the agent used. It is best to use a liquid fertilizer that you can administer together with the irrigation water. This has the advantage that it reaches the roots faster and can be better absorbed.

Oleander tolerates organic fertilizers very well

If you like it more natural, you can of course also use natural fertilizers such as compost, stable manure and horn shavings (€32.93). These fertilizers also release their nutrients very slowly, so that over-fertilization is practically impossible. Provide your oleander with organic fertilizer in early spring and early summer, which is thoroughly worked into the substrate. When repotting (do this in early spring if possible!), the plant substrate can be enriched with compost and horn shavings (€32.93).

Extra tip: Fertilize oleanders with tea or coffee grounds

A very special and particularly cheap insider tip for the fertilization of plants that consume heavily, such as oleander, is the use of tea or coffee grounds. Coffee grounds in particular contain a lot of valuable nutrients and are valuable fertilisers, which are also produced free of charge in many households - and are usually thrown away. You can use coffee grounds fresh, but you can also dry them and then store them in an airtight container for the next use.

Fertilize oleanders with blue grain

Oleander can also be fertilized with blue grain, and many hobby gardeners have had very good experiences with it. However, with the very nitrogenous blue grain, over-fertilization can quickly occur, which stimulates shoot growth immensely, but hardly any flowers are formed - too much nitrogen in the fertilizer is poison for a rich bloom. However, if dosed correctly (be sure to follow the instructions!), you can't go wrong with blue grain. If you want to be on the safe side, you can also fertilize your oleander with compost at the beginning of the growing season - this ensures a balanced mineral balance.

Recognize nutrient deficiencies in good time

Yellow leaves are a sure sign of a lack of fertilization - especially if the oleander not only has a few yellow leaves, but many leaves turn yellow within a short time. A few yellow leaves are normal, however, and are a natural aging of the foliage. A puny flower or stunted flowers can also indicate a nutrient deficiency, often in combination with fungal or bacterial diseases.

tips

In the case of mineral fertilizers in particular, you should definitely follow the manufacturer's dosage instructions in order to avoid over-fertilization. However, if you meant it too well, this is not necessarily deadly. Pay attention to the edges of the leaves: if they turn brown and dry, you should reduce the amount and/or frequency of fertilizing or switch to another fertilizer. Unfortunately, this leaf edge necrosis remains visible for a very long time.

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