Opuntia monacantha - Prickly pear cactus

Opuntia monacantha is a fast-growing cactus that develops very elongated prickly pears. A beautiful, bright green, they provide a lovely setting for the bright yellow summer flowering. The large flowers bloom around the edges of the prickly pears, then produce pear-shaped fruits, ranging from green to red. Reaching 2 m in height in a few years, this Opuntia tolerates the mild winters of the Mediterranean coast. Elsewhere, it must be grown in a pot as an orangery plant and overwintered, sheltered from the cold.

Opuntia or Prickly Pear belongs to the large family of Cactaceae, a group of highly diverse plants that fascinates enthusiasts and collectors. This family includes nearly 90 genera with varied forms: some species adopt a spherical silhouette, like Ferocactus while others take on the appearance of candelabras, such as Trichocereus cuzcoensis, or present even more original morphologies (villous cacti...). Among all these cacti, the Opuntia genus occupies an important place with about 250 species. The most famous is undoubtedly the Prickly Pear, native to Mexico. Its fruits are widely consumed in Mediterranean regions, where the plant has gradually become naturalised. Often called "prickly pear cactus", Opuntia is easily distinguished by its architectural silhouette. It develops as flattened segments resembling prickly pears, which branch naturally as it grows. 
Opuntia monacantha is a species native to South America: Argentina, Uruguay, Paraguay and Brazil. It grows in humid subtropical or tropical lowland forests and on sandy shores, from sea level up to an altitude of 1,000 m. In these regions, it forms an imposing plant, developing a "trunk" up to 20 cm in diameter, which supports a mass of branched prickly pears that can reach up to 6 m in height! In our climates, it generally reaches 2 to 3 m in height when planted in the ground, and less when grown in a container in regions too cold for it to be permanently planted in the garden. Similarly, the prickly pears (called cladodes), which in its native habitat measure up to 30 cm in length and 12.5 cm in width, are usually slightly smaller. They have an obovate to elongated shape, sometimes even distinctly narrow. They are fleshy with a smooth surface and a bright green epidermis. Rather sparsely thorny, this prickly pear most often forms one to two thorns per areole (which are anatomically transformed leaves, the prickly pears themselves being stems). The areoles are scattered over the prickly pears; those located in the upper half of them are often thorny, the lower ones are not. Nevertheless, even if they are scattered, the thorns can measure 4 to 5 cm long and remain very prickly! Their colour varies from white to brown.
Opuntia monacantha is fast-growing (it has become invasive in Australia and South Africa after being introduced) and can form a dense shrub more than 1 m in height in 4 to 5 years, and in 10 years reach or exceed 2 m. If the climate suits it, it can indeed produce 3 to 10 prickly pears per year, branching naturally and abundantly. Young plants are therefore capable of flowering quite quickly, with beautiful, bright yellow corollas, with reddish central veins, and a dense heart of yellow stamens. The flowers measure 6 to 8 cm in diameter, and as is often the case with cacti, are particularly ornamental. They bloom in summer, appearing around the edges of the prickly pears. Once faded, they gradually transform into edible but uninteresting, pear-shaped fruits, 7 cm long and 5 cm in diameter, with a colour varying from greenish to reddish.

Opuntia monacantha is a species of prickly pear cactus useful for its size and superb flowering. In sheltered areas of the Mediterranean coast, it can reach a good size and thus structure a dry garden alongside slower-growing species. To vary forms, plant it with Agaves with sculptural rosettes, Yuccas with powerful trunks and generous blooms, Mother-in-law's Cushion (Echinocactus grusonii) with rounded shapes, or even Dasylirions with aesthetic thread-like leaves. In regions that are too cold, keep it in a pot to bring out only during summer, a guaranteed exotic feel!