Family: Cactaceae
Habitat: Coasts of Chile and Peru
Cultivation: Islayas are much more subsceptible to rot than other cacti. There are some tricks to ensure a healthy growth, such as surrounding the collar with sand or grafting your Islaya onto more robust cacti. Islayas grow very slowly and flower with difficulty.
Curiosity: Islaya is the name of the Peruvian locality where Backeberg, discoverer of the genus, found the first specimens of this cactus.


The genus Islaya is of uncertain attribution: according to some classifications it is a synonym of Eriosyce, while, according to others, it is a separated genus and includes a limited number of species (later merged in the already mentioned genus Eriosyce).

Islaya is native to Chile and Peru and it grows in arid deserts, where it never rains, and the only environmental humidity is provided by the coastal fog which moisten only an extremely thin and superficial layer of the soil. In order to exploit the little quantity of water, Islayas have developed a very superficial root system.

This genus includes species endemic of limited areas, such as I. laui, which can be found in an 10 square kilometers wide area, in a severe, completely desertic environment, where very few plants are capable of surviving; but it also includes species with a wide range of distribution, Such as I. grandiflorens var. spinosior.

They are small solitary cacti, spherical, provided with a taproot. They grow in arid and hostile environments such as high rocky cliffs, to which they cling with their strong roots. They maintain a small size (not exceeding 10 cm in height, usually) and grow very slowly. The stems, in some species, may form little clumps with multiple apexes.

The stem is furrowed by tubercles and is dark in color, with various shades from green to brown. The areoles may be extremely woolly in some species, such as I. laui, and are usually white in colour. In I. laui, the wool of the areoles is so extended that it gets to partially cover the stem, that ends up to look like a kind of cootn candy! From the areoles that sprout on top of the tubercle grow numerous strong spines, usually gray or black. On one areole, there is a central spine pointing clearly outwards, surrounded by more or less 20 (the exact number depend on the species) radial spines.

It blooms with difficulty and produces pale, usually yellow flowers. They sprout during the day and are solitary or in small groups on the top of the stem. These flowers are usually funnel-shaped and their diameter depend on the species. The floral tube can be scaled in some species, such as I. brevicylindrica.

The fruits are club-shaped or more globose, like balloons, red-pinkish, fleshy initially and dry when ripen.


Here are the main species of Islaya that you can find in the market.

  • I. bicolor
  • I. brevicylindrica
  • I. copiapoides (or I. islayensis var. copiapoides)
  • I. flavida
  • I. grandiflorens
  • I. grandis
  • I. islayensis
  • I. kraiziana
  • I. molendensis
  • I. omasensis
  • I. paucispina


Here are our cultivation tips:

  • Choose a sunny spot for your Islaya, as it needs plenty of direct light.
  • Always keep above 5°C, even in winter. However, they can survive brief frosts if the soil is maintained completely dry and if temperatures drop just below
  • freezing. A large temperature range between day and night is appreciated.
  • Water every 3-4 days in spring and summer and thin out with the arrival of autumn, until you stop watering altogether during the winter months.
  • Between one watering and the other the soil must have the possibility to dry out.
  • You can use a standard soil for cacti, light and very draining, or a mix of sand, soil and peat.
  • Fertilize at the beginning of the month during the growing season.
    Because of its small size and slow growth, it is not frequently repotted. Choose rather deep pots to easily contain the deep taproot.

Islaya can be propagated exclusively by seed. The seed must be kept fresh and buried in a humid sandy substrate at a temperature of about 25°C.

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