How to grow potted oleander? Master these care essentials

Oleander, also known as willow-leaf peach and half-year red, is an evergreen large shrub of the genus Nerium in the dogbane family Apocynaceae. When potted, it is often trained into a small tree form, with a plant height of 2 m to 3 m. The stem is upright and smooth, old branches are grayish brown, young branches are green, with strong branching ability, mostly growing in a three-forked pattern. The leaves are lanceolate, in whorls of 3, thick and leathery, with short petioles, 10 cm to 25 cm long, with sharp tips and wedge-shaped bases, dark green on the surface and light green on the underside, with a prominent midrib and entire margins. The petioles and inflorescence stalks are purplish red, and there is a small amount of milky sap in the branches and leaves. The cyme is terminal, with a corolla ranging from pink to deep red, funnel-shaped, 5-lobed, with wrinkles on the petals, mostly double or semi-double, with a relatively faint distinctive fragrance. The fruit is oblong, and the flowering period is from June to October. Common cultivated varieties also include white oleander, with white flowers. Variegated oleander, with markings on the leaf surface and red flowers. Pale yellow oleander, with pale yellow flowers. In the same genus there is also European oleander, also known as large red oleander, native to the Mediterranean coast, with purplish brown branches and larger leaves, elliptical-lanceolate in shape. The flowers are large, the inflorescence is dense, deep red, double, and of relatively high ornamental value.

Oleander is native to India, Iran and Afghanistan, and has a long history of cultivation in China, spread throughout urban and rural areas north and south. It prefers sufficient light and warm and humid climatic conditions. It is also slightly cold-tolerant, and in warm temperate regions it can overwinter outdoors without shedding its leaves. In the Beijing area, household potted plants can have their branches tied together and covered with a bag, placed in a wind-sheltered, sunny spot to overwinter. Oleander is vigorous by nature, tolerant of barren soil and drought, and not demanding about soil, but for potting it is still best to use ordinary potting soil that is loose, fertile and highly permeable, and avoid prolonged wetness and waterlogging in the pot. It has strong resistance to smoke, dust and various harmful gases.

Oleander is mainly propagated by cuttings. In April, in combination with shaping and pruning, cut vigorous branches about 15 cm long as cuttings. Several dozen can be tied into a bundle and soaked in a shallow basin of clean water, with the water depth reaching 1/3 of the cuttings. Seal the shallow basin tightly with a plastic bag and place it in high-temperature sunlight for exposure. After two weeks, roots will form; take them out and plant them separately in small tube pots or seedling bags with ordinary potting soil for care. Once the cuttings survive and sprout, select one robust bud to develop into a new plant, and remove the rest. When the new plant grows to 20 cm tall, repot it into a tube pot with an inner diameter of 20 cm, fill the pot soil up to the base of the new plant, that is, bury the original cutting in the soil, so that it forms a rhizome and produces a large number of fibrous roots, prompting the new plant to grow vigorously. The following spring, establish the trunk and carry out shaping and pruning to develop a full, strong plant with three forks and nine tops.

The base of old oleander plants often sends up many young shoots in clusters. When they grow to 10 cm long, they can be broken off with a heel and inserted into fully decomposed potting soil, kept shaded and moist; the survival rate is also very high.

Oleander is vigorous by nature, and cultivation and management are relatively extensive. For potted plants, repot and change the soil once every 2 years, and a small amount of long-acting fertilizer such as feathers and hoof and horn pieces can be placed at the bottom of the pot. During the growing season, apply liquid fertilizer 1 to 2 times as appropriate according to growth. Oleander tolerates pruning and has strong sprouting ability. Aged plants can be rejuvenated by pruning in spring in combination with repotting and changing the soil, cutting all branches off from the base to encourage new branches to sprout and restore vigor. Generally, plants should also be pruned moderately in spring to keep the plant shape well balanced and the tree vigorous.

In summer, potted plants should be watered and sprayed frequently to keep the pot soil and environment moist, but never allow prolonged wetness or water accumulation. Oleander also has another characteristic: as long as there is one instance of drought and dehydration or excessive water and waterlogging, the lower leaves of the plant will quickly all turn yellow and fall off, so watering must be timely and appropriate. After heavy pruning in early spring, pay attention to withholding water to prevent root infection and rot. Loosen the pot soil in a timely manner, and remove flowers promptly after they fade. In summer, aphids and red spider mites occasionally cause damage, and general pesticides can be used to eliminate them.