Oleander - Ornamental Tree

Oleander (Latin: Nerium oleander) is the only representative of the oleander genus (Latin: Nerium). It belongs to the dogbane family (Latin: Apocynaceae). This decorative ornamental plant originates from the Mediterranean, where it grows along watercourses and urban areas. In the wild, Oleander grows from Portugal to Morocco. It often reminds us of holidays in Greece, Turkey, and Croatia, where it grows abundantly along roadsides. Oleander is one of the most popular plants grown on sunny balconies and terraces. Especially in the evening, it emits an intoxicating fragrance, reminiscent of moments spent on holiday. Oleander is a tree/shrub up to 5 m tall, richly branched. In indoor conditions, it reaches a maximum height of 2 m. You can also keep it pruned at lower heights. It is an evergreen plant. The leaves are petiolate, arranged in whorls, lanceolate and leathery. The flowers are arranged in terminal panicles. They are stalked, pentamerous. Colors range from pink to red and, of course, white. The flowers truly emit an intoxicating scent, especially in the early evening. The fruit of oleander is a seed pod, similar to a legume. Numerous cultivars have been bred - with double flowers, various flower colors, variegated leaves, etc. The selection for cultivation is therefore vast, and Oleander can adorn any garden.

Growing Oleander

The plant originates from the Mediterranean and is therefore heat-loving and thrives in sunny, warm, and airy locations. After purchasing seeds, prepare a mini greenhouse or other enclosed container that will simulate a hotbed. The soil for seed germination should be rich in nutrients and constantly moist, as should the air in the container. If you're germinating exotic plant seeds, you can also rub them with juice from aloe vera leaves or soak them in it before planting in soil. You can heat the germination soil in the sun or in a microwave. Always read the germination instructions on the seed packet carefully and follow them accordingly.

After germination, transplant the oleander into a pot with a layer of clay pebbles at the bottom as a drainage layer. The plant does not tolerate waterlogging well. Therefore, the substrate should not contain peat, which absorbs water like a sponge. Instead, substrates with a sand content are more suitable. If the young transplanted seedling seems weak, you can still keep it covered with glass (like hibiscus, for example). Place it in a sheltered spot for now. After placing it in the chosen location, we no longer cover the seedlings. Oleander is heat-loving; there's no need to shade it.

Oleander needs abundant watering during warm months - preferably with settled water. If you're growing Oleander near heating or directly behind glass windows, we recommend misting the plant regularly. If Oleander lacks moisture, you'll notice its leaves starting to drop. In winter months, on the contrary, you can let the soil in the pot almost dry out and water sparingly.

Oleanders bloom from June to October. From April to August, we fertilize the Oleander with organic or combined fertilizers for indoor plants.

Suitable locations for Oleanders are warm balconies and south-facing terraces. If you plan to place the plant in your garden/terrace space, you can add larger stones to the pot to weigh it down and prevent it from being blown over by wind. During the first three years of the plant's life, we repot it annually; in subsequent periods, we repot every 2-3 years. Some plants need to be repotted up to 4 times before they develop a good root ball as the foundation for healthy growth.

After flowering, we prune the Oleander. For annual seedlings, we only remove the flowers after blooming. For older plants, we prune to one-third or half the length. If you perform a more thorough pruning of the Oleander, expect it to bloom only the year after next. Oleanders can withstand temperatures down to -11°C. However, we recommend overwintering this plant and placing the Oleander in a cooler location with temperatures around 8-12°C. A constant temperature (warm garage) during winter overwintering will ensure an abundance of flowers in the next season. If it's not possible to move and overwinter the Oleanders, you can try covering them with black non-woven fabric and wrapping the pot as well. However, it's 50:50 – the plant may freeze and die. It's worth moving even larger specimens in bulkier pots for winter.

If you'd like the Oleander as a bonsai and want to try shaping it, we recommend grafting Adenium onto an Oleander rootstock (annual seedling) instead.

Common Oleander (Nerium oleander)

The entire plant is highly poisonous! Fatal poisoning occurs after ingesting a single oleander leaf. Fatal poisoning also occurs if you merely prepare and consume food over a fire made from oleander twigs, or if you consume honey from oleander flowers. The toxicity affects the heart and increases cardiac activity tone. Symptoms of poisoning are similar to those from other poisonous plants – vomiting, diarrhea, tremors, cardiac arrhythmia, fever, dizziness. Ovine digoxin-specific Fab fragments – immunoglobulin – are used as an antidote. In medicine, oleander flowers are used to produce medications for cardiac arrhythmia and to treat skin conditions. Never attempt to make anything from oleander at home, nor try any self-treatment. This is a fatally poisonous plant!

In the garden, the Oleander serves fully as a decorative shrub with magnificent flowers in shades of pink.

Author: Hana Michalíková