Oleander (lat. Nerium oleander) is an evergreen shrub from the family Apocynaceae, and it can grow up to 6 m in height. It got its name because of the similarity of its leaves with olive leaves (Olea). Cultivation of oleander as an ornamental plant is common throughout Croatia, and the plant grows wild near Dubrovnik. It also grows wild in Greece, Portugal and the Mediterranean area.
Oleander has upright, smooth, thin and long branches. Oleander leaves are leathery and elongated. They are gathered in a vertebra or placed opposite. Large flowers with a pleasant smell are collected on the tips of the branches in pasty flowers, and they bloom from June to September. Oleander flowers can be white, yellow, red, pink and purple.
The fruits are 10 to 20 cm long and contain two quivers each containing many seeds that are covered with brown hairs.
Weather conditions for planting: sunny or slightly shaded places
Flowering time: from June to September
Height: up to 5 meters
Planting oleander
Oleander planting is usually done at the end of summer. There are no special requirements when it comes to land, and it tolerates salty soils well. Propagation of oleander is done by seeds or young shoots, or cuttings.
The seeds must be collected and stored immediately after ripening, so that they are not blown away by the wind. Seedlings obtained from seeds will not always give the originality of the plant from which the seeds were collected, because when oleander is pollinated, crosses with plants of other colors occur.
Propagation
If you want to get a plant that is identical to the mother plant, propagation in that case is done by cuttings, which is also the simplest way. The cuttings can be from 10 to 50 centimeters long, and are cut with a sharp knife or scissors. The cut should be just below the thickening on the branch where the leaves are located. Depending on the size of the cutting, it is necessary to remove the lower 2-3 pairs of leaves.
The cuttings prepared in this way are placed in a suitable container (usually glass) in August, which is filled with water so that the cuttings are at a depth of 5-6 centimeters. The water needs to be changed every second or third day. The container should be kept in a shaded place because direct sunlight can prevent rooting.
The cuttings should be well rooted after three weeks, so they can then be transplanted directly into the ground or into a pot. However, it is recommended to transplant the cuttings into a pot first so that they develop the root system even better by spring.
Another method of propagation by cuttings implies that the planting of prepared cuttings is done in a rooting substrate made by mixing equal proportions of peat and sand. It is recommended to add a hormone that will improve rooting. After planting, the substrate should be constantly watered in order to maintain humidity.
Cultivation of oleander is also possible in the continental part, where it is planted in large containers. When it comes to planting oleander in pots, they should be prepared so that a drainage layer is made at the bottom of clay pot fragments or coarse gravel, and humus is placed on top of it.
Cultivation of oleander
Proper oleander cultivation means ensuring sufficient amounts of moisture from spring to autumn, as well as regular feeding and pruning.
Plants grown in the continental area should be brought indoors with the arrival of colder weather. During the winter, it is best to keep oleander in bright rooms where the air is fresh and the temperature does not fall below 5 degrees.
The temperature should not be too high either, because keeping it in warmer rooms can cause the appearance of pests, which can cause the plant to lose strength and bloom less.
Maintenance and care
Whether growing oleander in containers will be successful depends on the quality of the soil’s supply of nutrients and regular maintenance, which includes fertilizing, watering, appropriate pruning and eventual protection against pests and diseases.
Oleander should be watered regularly and abundantly – during warm summer days and up to twice a day. Feeding with liquid fertilizer is done twice a week. During wintering, watering should be reduced as much as possible, and fertilizing should be stopped completely.
For more successful flowering, it is necessary to regularly remove dead flowers. After flowering, the oleander is pruned, during which two or three of the most beautiful branches are left, and all the others are cut at ground level. If you want to rejuvenate the plant, then it is cut to about 40 centimeters every year.
Greek oleander
Greek oleander is considered a serious weed in some tropical areas because it can grow between pineapple, banana, coconut or sesame crops, and it is grown here as an ornamental plant.
It has a smooth, upright and slightly branched stem that can grow up to 80 centimeters in height. The leaves are simple, oval and oppositely arranged, and can be up to 15 centimeters long. The flowers are orange-red in color and consist of five sepals, petals and yellow stamens. They bloom from May to mid-autumn and are attractive to butterflies and other insects.
Planting oleanders of this type is done during early spring. It needs a lot of moisture and a sheltered, sunny or semi-shady place. Like other species, Greek oleander can only be grown in containers in continental areas because it cannot withstand winter.
Diseases and pests
Diseases can include dry rot, especially during rainy summers, and canker, that is, a fungal infection that affects almost all parts of the plant. Infected parts should be removed immediately and destroyed by burning.
Oleander is prone to attacks by aphids, scale and woolly aphids. Aphids and aphids can be controlled with insecticides or a solution of ordinary soap. Both pests secrete honeydew, on which sooty fungi settle and the leaves turn black, begin to dry and eventually fall off.
The natural enemies of these lice are wasps and cone flies. Insect baits, which you will spread around the plants in large numbers, can also be useful for plant protection.
The use of oleander
The relative resistance and easy cultivation of oleander have made it a widespread plant. Many consider it a symbol of the Mediterranean, and it is grown exclusively as a decorative plant.
All parts of oleander contain heart-active glycosides follinerin and oleandrin, which means that this plant is poisonous. Symptoms of poisoning are slow heartbeat, vomiting, difficulty breathing and dilated pupils. The skin and lips flood and spasms occur, and severe poisoning can cause death. In pregnant women, it can cause strong uterine contractions and death.
There have also been cases of poisoning of people who ate meat roasted on oleander sticks or barley porridge that was mixed with an oleander stick during cooking.
Poisoning can also be caused by the honey collected by the bees on the flowers of this plant, and the plant juice of the flowers can cause allergic reactions and skin irritation. Domestic animals that bite the bark, flowers or leaves of oleander can also be poisoned.
Photo: Hans Braxmeier / Pixabay