to the genus gymnocalycium belong about seventy species of small cacti, native to South America; they usually have a globular body, or briefly elongated, and reach the 10-15 cm of diameter. Some species tend to tiller, producing some small plants, which develop on the sides of the mother plant. The body of the gymnocalycium is dark, sometimes greyish, or even purplish; they have areoles often showy, which carry short sharp thorns, sometimes curved.
In spring they produce large white, pink, red or yellow flowers. The gymnocalycium are much appreciated by lovers of succulents, for the ease of cultivation, the small size and also for the abundant blooms.
the >>Dutchman’s honeysuckle should be grown in a container, because they fear intense cold, in winter it is advisable to grow them at a minimum temperature superior to 5-8°C; some species can bear temperatures a few degrees below zero, but only if the soil is completely dry. They prefer to receive a few hours of direct sunlight, but avoiding sunny positions for too many consecutive hours, therefore they should be grown in a partially shady place.
From March-April to September-October, water frequently enough, when the soil is well dry, even leaving it dry for 2-3 days before watering. Every 15-20 days, mix the water from the watering with the fertilizer for succulent plants, poor in nitrogen and rich in potassium. During the cold months, water only sporadically the specimens that are grown in an apartment or in a heated greenhouse, otherwise avoid watering.
prefer not too rich and very well drained soils; a good universal soil is used, mixed with equal parts of sand and lapillus or pumice stone. These cacti do not develop very quickly, therefore they are cultivated in small containers, and are repotted every 2-3 years.
is done by seed, in spring. The seeds are placed on the surface of a soil prepared by mixing peat and sand in equal parts; the substratum is to be kept humid until the germination; the seeds are kept in a shaded place.
Pests and diseases
are very afraid of the cochineal, also radical, and the rottenness due to water stagnation.
During the summer, water abundantly, while in the cold months we recommend letting the compost used for cultivation dry completely. Some species produce shoots
The side panels can be removed (in summer), left to dry for about three days and then planted.
Gymnocalycium andreae: The most common species
G. Andreae: Originally from Argentina, it is characterized by a bulbous stem of almost dark color, about 3 centimeters wide. The central spines are from 1 to 3 and white, while the radial spines are usually from 6 to 8. The flowers are bright yellow and about 4 cm wide.
G. Baldianum: native to Argentina, has a stem 4 or 5 centimeters tall, 6 or 7 wide and dark green in color. The radial spines are 5 and 5 or 6 cm long, while the central ones are completely absent. The flowers are about 4 cm long and red.
G. Denudatum: species native to Brazil, with a light and intense green stem. The main characteristic of this plant are the radial spines (there are no central ones) which are 6 to 8 and yellow in color. These spines, usually curved upwards and 8-10 cm long, appear “similar” to spider’s feet. Hence the nickname “Cactus spider”. The flowers are 6-7 cm long and white or pale pink in colour.
The specie più belle vi vi segnaliamo il NIGRUM chiamato così for le sue tipiche spine nere.