Opuntia robusta - Wheel cactus

Opuntia robusta, the Robust Prickly Pear, is a remarkable prickly pear cactus species known for its large, exceptionally thick blue-grey pads and its vibrant yellow summer flowering. This Mexican cactus is prized for its unusual appearance and tasty fruits. It thrives in Mediterranean coastal gardens or in potted arrangements on a sunny terrace. This cultivation method allows it to be sheltered from cold, damp conditions in winter.

Belonging to the Cactaceae family, Opuntia robusta is a small succulent bush that can reach 1 to 2 metres in height. This species is native to the arid and semi-arid regions of central and northern Mexico. It grows naturally in rocky, well-drained soils. Its habit is upright but may become spreading with age, forming a dense clump. Its growth is relatively fast for a cactus. Young cladodes have extrafloral nectaries that secrete nectar to attract ants, which help deter herbivores. Over time, the bark and mature stems take on a greyish hue. The Robust Prickly Pear develops thick, circular pads, measuring up to 40 cm in diameter, displaying a lovely blue-grey colour. These pads, sometimes wider than they are long, make it easily recognisable. The areoles, spaced 4 to 5.5 cm apart, bear yellow to brown glochidia and may have 2 to 12 white thorns with darker bases, reaching up to 5 cm in length. Flowering occurs in summer, from June to August. The yellow cup-shaped flowers measure 6-7 cm in diameter and attract numerous pollinators, including bees and beetles. The fruits that follow are spherical, red, and measure up to 8 cm long; they are edible and prized for their sweet, slightly tangy flavour. They contain many small black seeds. Its species name, "robusta", refers to the size of its cladodes. In its native Mexico, this species is widely used for human and animal consumption. Its cladodes or "pads" are eaten as nopalitos, a traditional ingredient in Mexican cuisine, while its sweet fruits, called tunas, are enjoyed fresh or processed into juice and jams. Opuntia robusta is also used to establish defensive hedges thanks to its sharp thorns and serves as livestock fodder during droughts.

Opuntia robusta is ideal for creating focal points in a dry Mediterranean coastal garden. Its massive silhouette and blue-grey colour harmonise with plants such as Agave americana, Dasylirion longissimum, or Yucca rostrata, which share similar soil and exposure requirements. It can also be used as a defensive hedge thanks to its deterrent thorns. In a wide, shallow container, it adds a striking, exotic touch to a sunny terrace. Ensure it is placed in a spot sheltered from winter moisture to guarantee its longevity. A good potted pairing could include creeping succulents like Sedum palmeri or hardy Delosperma for contrasting texture and colour.