Oleanders are available in a wide variety of flower colours, from pink, red, yellow and white and everything in between, with single, double or full flowers.
They bloom from the beginning of summer until the end of September. The plant is an evergreen and can reach a height of 5 metres in the regions where it belongs. It usually does not grow taller than 2 metres as a pot plant. It' s not hardy in the winter, so it should be placed indoors during winter. All parts of the plant are highly toxic because they contain the substances nereine and oleandrin. Eating its flowers, seeds or even a single leaf can kill a small child or pet. The sap of the plant can cause skin irritation.
How do i take care of an Oleander?
Oleander can be outdoors during summer. It can be placed outdoors in mid May, after the last night frost. It should be brought back indoors again at the end of October, as soon as there is a risk of night frost. It prefers a spot in direct sunshine, with high humidity, for example at the edge of a pond. Oleander likes to be placed in a large pot. It can be filled with regular potting soil, preferably with a bit of clay or loam, some fine sand and as some old manure or bone meal as a base fertiliser. At the bottom of the pot a good layer of chippings, gravel or clay granules can be added, because the plant likes to absorb water from underneath. Young plants can be repotted every year, older plants every three years. If repotting is difficult (e.g. when it comes to older pot plants) then only the top layer should be replaced from time to time, once more using a little clay or loam throughout the potting soil.
An oleander always feels thirsty. A generous daily dose of lukewarm water is very much appreciated, as well as a regular gift of small amounts of dried cow manure or ( pot plant) fertiliser. If the plants become too big or are bare on the underside, they can be pruned very easily. This is best done later on in the year, when the plant is brought inside. Just cut quite a bit of the branches off the old wood, until where you want the new branches to grow the next year. This also applies to the oleanders on the stems, where, of course, only the crown is pruned. Shoots that sprout after that will bloom in the coming summer. Pruning in spring is also an option, but this reduces the chance of flowering in the following season.
It is best to let the plants spend the winter in a cool, light place. The temperature for the regular pink and white cultivars should be just above 5 degrees Celsius. When the root ball is dry, the plant can often even survive a few degrees of frost, although this frequently results in leaves turning brown and falling prematurely. The somewhat more fragile dark red, yellow and full-flowered varieties like to stay a bit warmer while overwintering, around 10 degrees Celsius. In any event, the temperature must remain below 16 degrees Celsius. A winter temperature that is too warm can be the cause of the formation of (overly) long thin shoots in spring. Only a small amount of water needs to be given in the winter period, and no manure.
How should i prune an Oleander?
Oleanders can easily cope with pruning; a healthy plant will produce good, strong shoots again after being pruned. But before taking up the pruning shears, ask yourself why you want to prune the plant! Often a oleander is pruned because it has bare branches with just a few leaves and flower buds on its tips. Yet if you are going to prune for this reason, it really is a shame to waste the buds that you cut away. Flower buds that have not dried out after the winter will flower the following summer. A highly trimmed plant will produce little or no buds over the following year. It will grow vigorously and then, after two or three growth periods, produce the same result once again: long, bare branches with just a few leaves and buds at the tips.
All parts of the oleander plant are very toxic to animals as well as to both smaller and bigger people when consumed, and the plant sap can also cause (skin) irritation.
Only when a oleander has become really too big, will pruning be unavoidable. We can best prune our oleanders at the end of February/beginning of March. Around this time, the temperature usually rises a bit in the overwintering room and the plant sap starts to flow again. Decide which shape you want the plant to have. Next, cut away the branches that you find too long using clean, sharp pruning shears. A healthy oleander will develop buds even on the oldest branches. So you can basically cut away quite a bit. If you want an oleander bush that's lighter and more spaced-out, don't cut down to the main stems, but leave a few centimetres of the lateral branches in place. New twigs will grow on the lateral branches which will make it a more open shrub, which is, incidentally, more beneficial for the plant. The new, not yet wooded branches will dry out better, which reduces the risk of fungal infestation, especially during the following winter. If you have a shrub with exceptionally long branches stemming from the ground, cut these branches in varying lengths. Preferably leave the longest branches in the middle.
Can I progrogate Oleander?
Oleander responds well to cuttings. The best time to take cuttings is in June. For this purpose, larger cuttings with a length of 2 or at the most 3 pairs of leaves are cut with a sharp knife just below a pair of leaves. The lower leaves are removed, after which the cutting is put in a mixture of fine sand and some potting soil. In a warm, light location, the first roots will appear after a few weeks. The cuttings will also take root in water. The cuttings can be potted as soon as enough roots have formed.
What are common diseases and pests for an Oleaneder?
A pale green or somewhat yellowish leaf colour can indicate that the plant is in too dry a place in terms of humidity. Occasionally spraying it with water in dry periods will help. There are several ways to increase the humidity in the vicinity of the plant:
- Place large-leaved plants nearby, which absorb a lot of water.
- Put marshland plants (cyperus or umbrella) in a large pot next to it.
- Place a palm (in a closed pot) in a larger pot or platter filled with clay granules and keep it moist, or make a separate water garden by placing a pot or platter with clay granules next to the plants.
- Place bowls of water on top of the central heating and refill them regularly.
Even in an ideal location, it sometimes happens that the plant does not or barely flowers during a rainy or cool summer. In that case, the temperature has been too low to get the bud development underway properly. If the oleander did produce buds but they didn't come out or have even fallen off, then it has been too wet. If the problem occurs several years in a row, the plant may be removed from the rain while the buds are developing.
An oleander can suffer from infestations from aphids, scale insects and red spider mites. Several pesticides are available to combat these.
For instance, during wet summers plants can be attacked by the Ascochyta fungus: brown spots appear in the foliage and in the leaves and young shoots wilt. The fungus spreads via water droplets. The plant should then immediately be taken out of the rain. All affected parts must be removed from the plant, whereupon the pruning tools must be properly disinfected afterwards.
Another terrible infestation is oleander cancer: a wart-like, dark brown sprawl on the stems and sometimes light, watery patches on the leaves. The culprit, the Pseudomonas bacterium, is often present straight from the nursery, and strikes when the plant is in poor health. The affected parts can also be removed and disposed of. The tools must be properly disinfected after this treatment. Oleander cancer does not leave the plant, and can strike again as soon as the plant's condition deteriorates. Moreover, other oleanders in the vicinity could also become infected. If this is the case, it is often wiser to replace the plant.
My Oleander isn't flowering. Why is that?
Flowering oleanders are highly dependent on light and heat. Usually it has nothing to do with pruning. It's more about temperatures that are too low. Flowering is much better in warm years. They often don't want to flower at all or barely during a cold summer. So place it in as warm and light a place as possible.
Is an Oleander toxic?
All plant parts of an oleander are very toxic to animals as well as to smaller and bigger people when consumed, and the plant sap can cause (skin) irritation. Fortunately, most toxic plants are not very tasty at all, which means that their consumption (and the resulting damage) is mostly limited.
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