Common name: Fairy castle cactus, Night-blooming cereus, Barbed-wire cactus, Sword-pear, Dildo cactus, Triangle cactus
If you love succulents and cacti, Fairy castle cactus, the dwarf version of Barbed-wire cactus is a must-have in your garden. The taller variety can grow to a height of 2-6 meters, though the Fairy castle dwarf cacti only grow 10-20 cms high.
The name fairy castle comes from the tall columns that looks like spires and turrets, reaching to the sky. Their dark green stems have 3 or 5 sides having thin thorns that are about 1 cm long. Sometimes, the thorns are reduced to wooly, matted hairs along the edges of the stem.
Though not very common in houseplants, these cacti produce large white or yellow flowers that bloom only in the night, attracting moths and other nocturnal insects. They also produce small red fruits.
Flowering and fruiting takes a very long time, and is likely only in Fairy castle cacti that are older than 8-10 years. These plants love good sunlight, growing well in bright indirect sunlight, though they are capable of growing in partial shade.
As with all cacti, too much water can lead to root rot. So house plants should only be watered once in 3-4 days, reducing the frequency further in winter and rainy season.
Fairy castle cacti are mostly grown as ornamental plants, though the young stems and fruits of taller variants are eaten raw or cooked. They are also grown as border plants since the tall, spiny columns can prevent entry of foraging animals.
The dwarf variant of Fairy castle cacti must be grown in small pots in well-drained soil. Water only when the soil is completely dry. These cacti grow very slowly and hence do not need frequent fertilization. The bottom stems of this plant might become brown and woody over time, and that’s normal. These hardened stems support the new tall columns of stems that grow over time.
Propagation is very easy. Cut a piece of stem using a disinfected blade or knife, keep the cutting outside so that it forms brown calluses. These can then be planted in a succulent potting mix.
Acanthocereus tetragonus Fairy castle