Gymnocalycium saglionis
| Light | Bright light with some shade from harsh afternoon sun |
|---|---|
| Water | Moderate in growth; allow to dry between waterings, keep dry in winter |
| Soil | Fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9a–11 |
| Propagation | Seed (primary) |
| Toxicity | Non-toxic to cats and dogs |
Gymnocalycium saglionis is a large, solitary chin cactus from northwestern Argentina, and the biggest species in its genus. Mature plants form a stout blue-green to grey-green globe that can approach 30 cm across, armoured with heavy, curved spines and crowned in season with small pale pinkish-white flowers. Its bold ribs and formidable spination make it a striking and forgiving choice for collectors, and it is sometimes sold under its basionym Echinocactus saglionis or the common name giant chin cactus.
Description
Gymnocalycium saglionis is a large, usually solitary cactus that starts flattened-globular and becomes broadly rounded with age, in exceptional plants reaching close to 40 cm in diameter. The body is firm, dull green to bluish- or greyish-green, and divided into numerous broad ribs that are broken into prominent rounded tubercles. Each large areole carries a spreading cluster of stout, rigid spines — typically several radials and one or more centrals — that are curved, reddish-brown to blackish when young and greying with age, forming a dense protective cage over the plant.
Like other members of the genus, it has the characteristic "chin" — a small bump beneath each areole that gives Gymnocalycium its name. Flowers are comparatively modest for so large a plant: funnel-shaped, roughly 3–4 cm across, white to pale pink and borne in a ring near the crown through spring and summer. They are followed by rounded reddish fruits.
Distribution and habitat
The species is native to the mountains and foothills of northwestern Argentina, across provinces such as Catamarca, Tucumán, Salta and La Rioja. It grows on rocky slopes and in gritty, well-drained ground, often among grasses and low shrubs that give it a little seasonal shade. Across its wide range it varies noticeably in size, colour and spine strength, and several regional forms and varieties have been described by growers.
Cultivation
Gymnocalycium saglionis is one of the easier large cacti to keep, tolerant of a range of conditions and more forgiving of water than many desert species — though wet feet in cold weather will still cause rot. Grow it in a free-draining, mostly mineral mix and give it bright light; a little shade from the fiercest afternoon sun keeps the body a healthier colour and prevents scorch, while too much shade produces soft, pale growth.
Water thoroughly through the warm months once the soil has dried, then reduce sharply and keep the plant dry and cool over winter. A cold, dry rest not only prevents rot but also encourages the ring of flowers to form. The species is a steady grower that appreciates room for its roots — see Watering and Repotting for general technique.
Propagation
Seed is by far the usual method. The seeds germinate readily on a warm, damp mineral surface and young plants grow at a reasonable pace for such a large species. Because the plant is normally solitary and seldom offsets, vegetative propagation is uncommon; when offsets do appear they can be removed and rooted. See Propagation — seed for a full walkthrough.
Common problems
- Rot — the main risk, usually from a cold, wet winter or a slow-draining mix; the plant softens from the base.
- Etiolation — too little light makes the body pale, elongate and lose its firm, ribbed shape.
- Pests — mealybugs (white fluff in the areoles and among the spines) and root mealybugs are the most common; red spider mites can bronze the skin in hot, dry air.
See also
- Gymnocalycium — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Pests and diseases