Strophanthus GRATUS

Strophanthus GRATUS - Climbing oleander, Cream fruit, Rose allamanda, Strophanthus gratus.

Strophanthus is a genus of climbing shrubs and lianas in the dogbane family (Apocynaceae), numbering more than 35 species distributed across tropical regions of Africa and Madagascar. These plants are distinguished by strong, flexible stems, often reaching considerable length, and thin, leathery leaves arranged oppositely or with a slight spiral deviation. Large flowers of whimsical shape with long thread-like appendages on the petals give the genus special ornamental appeal.

The flowers of strophanthus are white, cream, yellow, or pinkish, often with a contrasting pattern. They feature characteristic elongated corolla lobes that can hang down or twist into a spiral. The fruits consist of two long follicles containing numerous seeds with a silky plume that facilitates wind dispersal. Many species of the genus have long been known for their rich content of cardiotonic compounds.

Strophanthus gratus is a tropical evergreen, spreading shrub or liana reaching 7.5 m (25 ft) in length. Leaves are elliptic, glossy, smooth, green, up to 15 cm (6 in) long. It blooms from spring to autumn with very attractive flowers in shades of cream and pink. The flowers have a delicate fresh scent.

The species is not only ornamental but also very fragrant, with its scent almost indistinguishable from that of a rose.

The seeds are large, about 10 mm (0.4 in) long, oblong, light brown, equipped with a long silky plume that aids wind dispersal. Germination is usually stable - around 60-75%.

Before sowing, seeds are soaked for 12 hours in warm water or a solution of a mild growth stimulant. Planting is carried out in a light substrate of peat and sand or leaf mold and perlite, with seeds buried 5-8 mm (0.2-0.3 in) deep with the tail pointing up. Sowings are placed in a propagator or covered with film and germinated in light, but not sun, at a temperature of 24-28 °C (75-82 °F). Stable moisture is maintained, and daily ventilation is provided.

Seedlings appear on average after 15-25 days; the minimum period is about 10 days, and the maximum possible is more than 40 days. After the appearance of a pair of true leaves, young plants are carefully potted into individual containers. The plant can also be propagated by semi-lignified cuttings, but rooting requires greenhouse conditions and high air humidity.

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Strophanthus prefers bright diffused light and warm conditions. The optimal temperature during the period of active growth is 22-28 °C (72-82 °F). Direct midday rays can cause sunburn, so light shading is required. In winter, the plant requires cooler conditions - around 12-15 °C (54-59 °F); during this period partial or complete leaf drop is possible, which is normal for the genus. In spring, with rising temperatures and increasing day length, the plant leafs out again.

Watering is carried out moderately: the substrate should dry out slightly in the top layer between waterings. Stagnation of water is eliminated, since the roots are sensitive to waterlogging. In winter, watering is reduced to a minimum. In warm weather, it is beneficial to periodically mist the leaves or provide higher air humidity, especially in hot weather.

Strophanthus requires a light, breathable substrate - a mixture of leaf mold with the addition of sand, perlite, or coconut coir. A suitable soil reaction is neutral or slightly acidic. Fertilizer is applied every two weeks during the active growth period, predominantly with complex mineral fertilizers.

Most species require support - a trellis, netting, or taut guide wires, since the shoots are climbing and lengthen rapidly. The sap of the plant is toxic, so all work, including pruning and repotting, is carried out with gloves.