Named after Leopoldo horst
(1918-1987) German-born Brazilian cactus collector and exporter in Rio
Grande do Sul.
isa a distinctive large cactus, minimally spined with a green
ball-shaped body. Usually solitary or slowly clustering as they age.
Smooth, globoid, shiny green, up to 20(-25) cm in diameter.
Ribs: 5-6 cm wide, rounded, somewhat acute, deeply furrowed.
Spines: Few (usually 5 of which one pointing downward others to
the sides) , yellowish white, sparse, straight to slightly curved,
definite and very irregular, up to 3 cm long.
Flowers: White, pale pink,
pink or pale purplish up to 11 cm long and in diameter.
Fruits: Ovoid, blue-green.
G. horstii are very similar if not identical, both have very
similar great pink flowers and the same (usually) five ribbed
appearance, and good, yellow spines.
Cultivation: Very easy to grow, this
plants offers no cultivation difficulties. Summer grower needs moderate
to copious waterings in summer
(It enjoy more water than the average cactus).
resistant if kept dry in winter -4° C.
with a high potassium fertilizer in summer.
Light shade. (Keep
out of hot, direct sun or will burn badly but hot, blazing afternoon sun
taking it well, just bronzing a bit)
Propagation: Seeds (seldom produces offsets)