🌱 Morphology
   The “mother-in-law’s seat”… A globose, slow-growing cactus, generally solitary, although it may produce basal offsets with age. Adult specimens can reach approximately 1 m in height and 80 cm in diameter, gradually acquiring a somewhat more cylindrical shape. The body is deep green and features numerous deep ribs, generally more than 20 in adult specimens.

The areoles are densely arranged along the ribs and develop numerous yellow or golden spines. Each areole features several radial and central spines, the latter being sturdier and longer, reaching several centimeters. The dense covering of golden spines gives the plant its appearance of a large yellow sphere and its common name in America: golden barrel.

🌍 Distribution, habitat and family
Family Cactaceae. It is a species endemic to Mexico, with a natural distribution from Zacatecas to San Luis Potosí. It grows in dry scrubland and semi-desert environments, on rocky slopes, where drainage is very rapid.

Its natural populations are found at approximately 1,400 to 1,900 m above sea level. This high altitude is relevant for its cultivation: although it lives in a warm and arid region, nighttime temperatures and winter spells can be considerably lower than those that would correspond to a strictly lowland cactus. The currently correct name is Kroenleinia grusonii; Echinocactus grusonii, the name by which it has historically been known, is its homotypic synonym.

❄️ Temperature
USDA Zone 8b Tolerates minimum temperatures of up to −10 ºC in dry specimens, according to cultivation observations carried out at Desert CITY. This resistance should be interpreted as an observed tolerance to a specific minimum temperature, and not as a direct equivalence between −10 ºC and USDA Zone 8b.

The high altitude of some natural populations helps explain that it is not exclusively a thermophilic cactus. In cultivation, cold resistance increases considerably when the plant is completely dry, well acclimatized, and protected from persistent moisture. The main winter risk is not solely the low temperature, but the combination of cold and wet substrate.

☀️ Lighting
Indicative PAR DLI: 20–30 mol·m⁻²·day⁻¹. It is a cactus with high light demands. Intense lighting promotes compact growth, well-defined ribs, and dense, golden spines.

Young specimens must be gradually acclimatized to direct sunlight. Once adapted, they can receive high radiation. During exceptional spells of intense heat, especially in small containers, it may be advisable to provide some protection during the middle hours to prevent excessive overheating of the body.

💧 Growth cycle and watering
Winter dormancy. Its cycle is related to the warm temperatures and seasonal rainfall, but the high altitude of its natural populations introduces a marked temperature range between day and night. Growth is especially favorable during spring and summer, when temperatures allow for adequate root activity.

During the active period, it is recommended to perform abundant watering and let the substrate dry out completely before the next watering. In autumn, watering should be gradually reduced, and during winter, the plant should be kept practically dry. It should not be watered at very low temperatures.

During spells of extreme heat, it may also temporarily slow down its activity. In these circumstances, heat should not be interpreted as a signal to automatically increase watering: first, it must be checked that there is active growth.

🌸 Flowering
Specimens need to reach considerable maturity before flowering. (about 18 years) The flowers appear forming a ring on the upper part of the body, near the apex, and are yellow, with a bell-shaped to broadly infundibuliform appearance.

Flowering occurs mainly during the warm months, approximately in summer. When cultivated in Spain, it can be expected, as a guideline, between June and September, depending on the age of the specimen, the accumulation of daylight hours, and spring temperatures.

🌿 Nutrition
During the active growth period, Desert CHOICE® Cactaceae is recommended, applied after watering. Before flowering, it can be supplemented with Desert CHOICE® Flowering. It is not recommended to fertilize during winter dormancy or when the plant is subjected to extreme temperatures.

This is an inimitable xerophyte cultivated in Madrid in a technological square pot and with the substrate activated with mycorrhizal fungi.

📏 The sizes of our basic collection xerophytes are as follows:

S -> 9cm x 9cm

M-> 14cm x 14 cm

L->16cm x 16 cm

Large containers for large specimens, with price varying by age and diameter

* As this is an online purchase, the appearance of the specimen sent may vary slightly from the product image. The description on the photo specifies the measurements of the plant, but this can also vary slightly, because it is a living being! Each of the plants at Desert CITY has unique characteristics.