Islaya Backeberg (1934)

named after the origin
globular, later elongated, with a dense felted apex
flowers only a few centimeter long, usually yellow
fruits red, floccose haired, at ripeness a hollow elongated fruit, opens at the base
seeds dull black spotted

Highslide JS


southern Peru to northern Chile
from near the coast to ca. 3280 ft (1000 m) altitude
rocky deserts and mountains

Growth period

half to full sunny and hot location, preferably very close to the greenhouse roof
protection against blazing sun by shading
extraordinary dry conditions for growing, only at intense heat somewhat mist or spray around evening
very sparse moisture!
plants of this genus grow very slow and are very tricky in cultivation

Winter period

light, cold and dry conditions at ca. 46°F (8°C)


minerally, permeable to water and porous

Islaya grandiflorens Rauh & Backeberg (1957)
Highslide JS

Field number

KK351 - collected by Karel Kníže


Atico - mile 433 (kilometre 697) of the Pan-American Highway
in 330 ft (100 m) altitude


grand flowering Islaya
ca. 3.9 in (10 cm) high and Ø, gray green to green
16–21 ribs
spines initially blackish, at the base red or yellowish, then horn colored, lastly ash gray with black tip
10–15 radial spines, ca. 0.4 in (1 cm) long, thin, partly parted
2–3 central spines, 1 in (2.5 cm) long
apex small, yellowish
flower ca. 1.6 in (4 cm) Ø, yellow, outside is greenish
fruits ca. 1.2 in (3 cm) long, carmine red

Flowering time

May–June in cultivation
mainly in December in habitat
3–4 years from seed
Synonyms Neoporteria islayensis fa. grandiflorens (Rauh & Backeberg) Donald & G. D. Rowley (1966)
Eriosyce islayensis
(C. F. Foerster) Kattermann (1994)
CITES Appendix II
Description of "Kakteen von A bis Z" by Walter Haage with courtesy by Kakteen-Haage made available.