The White Oleander, scientifically known as Nerium indicum, is an evergreen shrub belonging to the Apocynaceae family and Nerium genus.
This cultivated variant can be found across both northern and southern China, particularly in Yunnan, Guangdong, and Guangxi. It’s commonly grown in botanical gardens and parks.
Despite its beauty, the white oleander is highly toxic, with the whole plant possessing poisonous properties. If ingested, it could lead to serious health risks, even death. Therefore, it’s essential to handle it with caution.
However, the toxicity of the white oleander is lower than the red oleander, making it frequently used for medicinal purposes.
Its white flowers or tender leaves are often brewed as a soup or dried and ground into a capsule for consumption. It has emetic and antispasmodic properties.
The White Oleander is a cultivated variant found in both northern and southern China and is popular as an ornamental flower. It has the capability to resist smoke, dust, toxins, and purify the air, thereby protecting the environment.
The leaves of the oleander show strong resistance to harmful gases like sulfur dioxide, carbon dioxide, hydrogen fluoride, and chlorine. Thus, it is often planted in industrial and mining areas.
It is commonly found in botanical gardens and parks.
Oleander is generally divided into red oleander (Nerium indicum Mill.), yellow oleander (Thevetia peruviana (Pers.) K.Schum.), and white oleander, the latter of which is a cultivated variant. It is found all over China, particularly in Yunnan, Guangdong, Guangxi, and Hebei.
Domestic Distribution: Cultivated in the south.
Foreign Distribution: Mediterranean.
Hubei Distribution: All over the province.
White oleander is an evergreen shrub that can grow up to 5 meters tall. It has grey-green branches that contain a watery sap.
The young branches have ridges and are slightly hairy, but the hair falls off over time. Leaves are 3-4 per whorl, with lower branches being opposite. They are narrowly elliptical, with acute tips, cuneate bases, and curled leaf margins.
The leaves are 11-15 centimeters long and 2-2.5 centimeters wide. The leaf surface is dark green and hairless, while the back is light green and has numerous depressions. Young leaves are sparsely hairy, but the hair falls off over time.
The midrib is sunken on the leaf surface and raised on the back. The lateral veins are flat on both sides, thin, densely parallel, and reach up to 120 on each side, extending to the leaf margin.
The leaf stalk is flat, slightly wider at the base, 5-8 millimeters long, and like the branches, it is hairy when young but becomes hairless over time. The leaf stalk has glandular structures inside.
The inflorescence is umbel-like and born at the top, with several flowers attached. The total flower stalk is about 3 centimeters long and slightly hairy.
The flower stalk is 7-10 millimeters long. The bracts are lanceolate, 7 millimeters long, and 1.5 millimeters wide. The flowers are fragrant.
The calyx is deeply 5-lobed and red, lanceolate, 3-4 millimeters long, and 1.5-2 millimeters wide. The outer surface is hairless, and the inner base has glandular structures. The corolla can be deep red or pink, but cultivation has introduced white or yellow variants.
When the corolla is single and 5-lobed, the corolla is funnel-shaped, about 3 centimeters long and in diameter.
The corolla tube is cylindrical, with the upper part expanding into a bell shape, 1.6-2 centimeters long. The inner surface of the corolla tube is covered with long soft hair.
The throat of the corolla has 5 wide scale-like secondary corollas, each of which is torn at the top and extends beyond the throat of the corolla. The corolla lobes are ovate, round at the top, 1.5 centimeters long, and 1 centimeter wide.
When the corolla is double and has 15-18 lobes, the lobes form three rounds. The inner round is funnel-shaped, and the outer two rounds are radial, splitting to the base or every 2-3 pieces are connected at the base.
The lobes are 2-3.5 centimeters long and about 1-2 centimeters wide. Each corolla lobe has a long oval scale that is torn at the top.
The stamens are attached to the middle of the corolla tube, the filaments are short, covered with long soft hair, the anthers are arrow-shaped, enclosed, connected with the stigma, have ears at the base, taper at the top, and the anther septum is elongated and filamentous, covered with soft hair.
There is no flower disc; the carpels are 2, separate, covered with soft hair, the style is filamentous, 7-8 millimeters long, the stigma is nearly spherical, and the tip is convex. Each carpel has multiple ovules.
There are 2 follicles, separate, parallel or connected, elongated, narrower at both ends, 10-23 centimeters long, 6-10 millimeters in diameter, green, hairless, with fine longitudinal stripes. The seeds are elongated, narrower at the base, blunt at the top, brown, the seed coat is covered with short rust-colored soft hair, and the top has yellow-brown silky seed hair.
The seed hair is about 1 centimeter long. It flowers almost all year round, with summer and autumn being the most prosperous periods. The fruiting period is generally in winter and spring, and it rarely bears fruit when cultivated.
Oleander is adaptable and easy to manage, whether planted in the ground or in pots. For ground planting, transplantation should be done in spring, with heavy pruning during transplantation. Winter protection is essential. The branches and leaves are prone to scale insect damage, so prevention and control are necessary.
For potted oleander, in addition to requiring good drainage, they also need sufficient fertility. Spring sprouting requires shaping pruning. The long and weak branches in the plant can be cut off from the base.
For the dense branches inside the canopy, some should also be thinned out to distribute the branches evenly and maintain a full tree shape. After 1-2 years, repotting should be done, which should be performed after pruning.
Summer is the period of vigorous growth and flowering of oleander, requiring a large amount of water. In addition to watering once in the morning and evening every day, if you see the pot soil is too dry, you should increase the spraying once to prevent wilting of the tender branches and affect the flower’s life.
After September, you need to withhold water to inhibit the plant from continuing to grow, allowing the branch tissues to mature, increasing nutrient accumulation, and facilitating safe wintering. The wintering temperature needs to be maintained at 8℃～10℃, and if it is lower than 0℃, it will defoliate.
Oleander is a plant that likes fertilizer. In addition to applying sufficient base fertilizer for potted plants, during the growth period, fertilizer should be applied once a month.
(1) Pruning must be timely. Oleander branches have a characteristic of dividing from one to three at the top, and they can be pruned and shaped according to needs. If a three-pronged nine-top shape is needed, a part of the three-pronged top can be cut off to split into nine tops.
If nine tops and eighteen branches are needed, six branches can be left, cut off from the top leaf axil, and eighteen branches can be grown. Pruning should be done after each flowering. In the north, the flowering period of oleander is from April to October. Faded flowers should be removed in time to ensure concentrated nutrients.
Generally, pruning is divided into four times: one is after the Grain Rain in spring; the second is during July and August; the third is in October, and the fourth is in winter. If you need to bloom indoors, move to a sunny place indoors around 15℃.
After flowering, prune immediately, otherwise, the flowers will be small and sparse, or even not blooming. Through pruning, the branches are evenly distributed, the flowers are large and bright, and the tree shape is beautiful.
(2) Root thinning must be timely. The growth of oleander’s fine roots is relatively fast. The three-year-old oleander, planted in a pot with a diameter of 20 centimeters, can be filled with roots and form a ball by July of the same year, hindering the penetration of water and fertilizer, affecting growth. If the roots are not thinned in time, wilting, leaf fall, death, and other situations will occur.
The best time for root thinning is from early August to late September. At this time, the roots have entered dormancy, which is a good opportunity for root thinning. The method of thinning the roots: use a fast shovel to cut off the yellow fine roots around it; then use a three-pronged hook to thin along the main root.
Approximately half or one-third of the yellow fine roots are thinned, and then replanted in the pot. After root thinning, put it in the shade and water thoroughly to keep the pot soil moist. Keep it in the shade for about 14 days, then move it to the sun.
For ground-planted oleander, in mid-September, the yellow fine roots should also be cut around the main stem. After root cutting, water, and apply a thin liquid fertilizer.
(3) Fertilizer and water must be timely. Oleander is a plant that likes fertilizer and water, and likes neutral or slightly acidic soil.
Cutting can survive in both spring and summer. Cut off the robust branches and insert them into fresh water for about 10 days, maintaining the freshness of the water. After insertion, the branches can root in advance to improve the survival rate of the plant. The temperature should be controlled at 20-25℃ during this stage.
When the roots grow out in the water, they can be cut. Before cutting, use chopsticks to make a hole in the soil to avoid damaging the roots of the branch. The bifurcation ability of the old stem base of oleander is relatively strong, and a large number of tender branches can often be grown, so these tender branches can be fully utilized.
When choosing branches, choose those with a semi-woody degree and retain the three small leaves at the top, insert them into the base, and pay attention to the management of water and nutrients, and the survival rate can be greatly improved.
The survival rate of layering propagation is not as high as that of cutting propagation. Generally, the buried part is first cut in a ring with a knife, and then buried in the soil. After about 2 months, it can be cut off from the mother plant, and it can be transplanted with soil the next year.
When layering, pay attention to the depth of cutting. Because the cutting place is easily affected by the environment, bacteria breed or other diseases are infected, which is not conducive to the survival of layering.
Effects and Functions of White Oleander
White oleander is also a very useful Chinese medicine. It tastes bitter and astringent, has a neutral nature, is non-toxic, and has diuretic, laxative, blood-activating, lump-resolving, stasis-removing, and cough-relieving effects. Modern medicine has proven that white oleander also contains trigonelline.
Generally, white oleander is preferred for medicinal use, and red oleander, which is toxic, is generally not chosen for medicinal use. The diuretic effect of oleander is particularly good, and it can be used to treat edema, ascites, foot swelling, constipation, and difficult urination.
The flowers of the white oleander have a charming faint fragrance, and the flowers are concentratedly grown at the top of the shrub branches. The white flowers are as white and bright as snow.
In April, the flowers are all over the mountains, the peach blossoms are in full bloom, and the apricot flowers are sparse. The spring colors are so enticing that they can’t be avoided. In the season of falling flowers, the white oleander is a beautiful landscape, the flowers are settled, and the white petals fluttering are so charming.
Flower viewing can not only cultivate one’s temperament, add life interest, but also beneficial to physical and mental health. Colorful flowers can regulate people’s emotions, and the white oleander is a late artificially cultivated color.
White can give a refreshing, quiet, and solemn feeling. As for the effect of flower fragrance, it is even more magical. The light white oleander can relax people’s nerves and has the effect of refreshing and pleasing the mind.
Flower Language of White Oleander
The flower language of the white oleander is pure friendship, be careful and prudent. The flower color of the white oleander is clean and holy, just like pure friendship without interest mixing, you can give the white oleander to your best friend, representing your affection for her, but the white oleander is poisonous and needs to be handled with caution.
Peggie was once a high school mathematics teacher, but she set aside her chalkboard and textbooks to follow her lifelong passion for flowers. After years of dedication and learning, she not only established a thriving flower shop but also founded this blog, “Flowers Library”. If you have any questions or wish to learn more about flowers, feel free to contact Peggie.
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