Gelsemium sempervirens - Yellow jessamine

Gelsemium sempervirens, also known as Evergreen Gelsemium, is a climbing perennial plant with beautiful yellow flowers with a sweet fragrance. Despite its charm, it is rarely planted in gardens due to its low cold resistance, which limits its hardiness to -5/-6°C (23/21.2°F). This species, sometimes called Evening Trumpet Flower or Carolina Jasmine is however well-known in the world of homeopathy. With rapid growth, it does not exceed 3 metres (10 feet) tall, adorns itself with beautiful shiny foliage, and can perfume, in spring, a whole section of the garden or terrace. Apart from its susceptibility to cold, it is an easy plant to acclimatise to partial shade, in ordinary soil.

Gelsemium sempervirens belongs to the Loganiaceae family. Native to the Southeastern United States, specifically the states of Carolina, Virginia, Tennessee, and the Eastern part of Texas, it is also found in northern Mexico and southern Guatemala. It grows in brush, woods, forests, pine forests, and fallow land. Not very hardy, it can only be grown in open ground in areas where the temperature does not drop below -5/-6°C (23/21.2°F) for short periods. This small perennial liana will not exceed 3m (10ft) in all directions, with a rapid growth rate. Flowering is quite brief but abundant in spring or early summer, and it sometimes blooms again in autumn in hot and dry climates, thanks to the return of rain. The plant produces, on short stems, in the axil of the leaves, clusters of tubular flowers measuring 3cm (1in), with a soft yellow colour and a pleasant fragrance that attracts many pollinating insects. The fruits produced are small, round, and flattened capsules. The evergreen foliage is composed of leathery leaves, shiny dark green, taking on bronze to violet hues in cold weather. These leaves, 4 to 8 cm (2 to 3in) long and 2 to 3cm (1in) wide, are opposite, lanceolate in shape, and have short petioles. They contain a highly toxic substance for humans, while the plant's roots are used in the composition of several homoeopathic medicines. The nectar of the flowers, according to some sources, may be harmful to our bees*.

The Carolina Jasmine climbs on bushes, trellises, arches, pergolas, stair railings, or balconies, but also crawls along the ground. Plant it in a container on a terrace to fully enjoy its intense fragrance. In its country of origin, this small liana is widely used in urban gardens, where it is planted along fences and walls. It could be combined, for example, with Sollya heterophylla, a purple passionflower (Passiflora Incense), or a white one (Snow Queen), which would take over its flowering in the heart of summer.

*Some studies tend to suspect that the nectar of Gelsemium sempervirens may be harmful to bees due to the presence of gelsemine, a potentially harmful alkaloid for the hive, and possibly for humans consuming honey made from a large quantity of these flowers. In the absence of more in-depth and precise data, it is recommended to cultivate this plant preferably in a closed space such as a greenhouse or conservatory, devoid of pollinating insects.