Pelargonium tetragonum

Pelargonium tetragonum, also known as the square-stalked geranium, is a botanical species that is rare in cultivation. It grows in very dry environments in South Africa. This perennial plant is a beautiful curiosity. It produces succulent, jointed, angular stems that trail on the ground or support themselves on neighbouring plants in nature. Its foliage is aromatic. Its tiny spring flowers are white with red markings. It requires plenty of sun and well-drained, dry soil in summer. Outside mild regions, it should be grown in a pot to protect it from humidity and cold.

Pelargonium tetragonum is endemic to a small region in southwestern South Africa, ranging from Worcester to Grahamstown. It is a perennial plant belonging to the Geraniaceae family, like all geraniums and pelargoniums. Branches emerge from the stump to form a loosely dense mass about 1.8 to 2m (6 to 7ft) wide or tall. These branches are fleshy, smooth, and brittle, composed of square or triangular segments that are sometimes lobed. The foliage remains evergreen from autumn to the end of spring, becoming somewhat deciduous in summer when the plant enters a period of rest. The soil should be dry during the resting period. The medium green leaves are palmate and divided into 5 lobes. They are sometimes marbled with reddish tones. This foliage is quite soft to the touch. It is equipped with glandular hairs that secrete an aromatic essential oil. When touched or crushed, the leaves emit a resinous and camphor-like fragrance. Flowering occurs between March and June, depending on the climate. To induce flowering, the plant needs sufficient sunlight and a respected summer rest period. The flowers are small and delicate, grouped in pairs. They range from light pink to creamy-white in colour. They often have 4 to 5 petals, with the upper 2 petals being larger and veined with red.

Pelargonium tetragonum is a collector's plant reserved for experienced gardeners. It can be planted in a sunny rockery in mild coastal gardens, sheltered from wind and foot traffic, where it will find a favourable climate. Elsewhere, cultivation in pots is possible, but it requires some skill: respecting the biological rhythm of this species is essential to see it bloom and thrive for several years. It is a frost-sensitive pelargonium that perishes below -3°C (26.6°F).