Gymnocalycium Riojense

Gymnocalycium Riojense

(You will receive a very similar plant to the one in the picture. It may or may not be blooming at the time of your purchase. This plant is shipped in its pot to prevent any damage to the roots).

Forms flat greyish/brown to olive/green stems with (usually) three spider like spines per areoles, it is fairly rare in cultivation but easy to grow.
is a dark skinned solitary Argentinian cactus with almost useless spines making it relatively easy to handle. G. rionense is one of the most variable Gymnocalycium. Will eventually  offset after a considerable period of time.

Stem: Flattened globose, brownish olive green, 1-8 cm tall up to 10 cm in diameter. Apex depressed often spineless.

Ribs: 10-12, flattened, without prominent chin-like protrusions..

Areoles: Oval with white felt.

Spines: All radials 3 (to 7) yellowish-white to light-brow with dark tips when young, becoming grey with age, spider-like, slightly curved, flattened against the stem, one pointing downward the other to the sides, up to 2 cm long.

Flower: White to pinkish-brown with a pale pink or red center up to 3,5 cm across, tube short.

Blooming season: Flowers are produced in late spring and remain open for up to twelve days.

Habit: Usually solitary in habitat, but occasionally branching basally in cultivation.

Stems: Flattened to globular, green to coppery-brown, spherical up to 10 cm in diameter.

Ribs: 13-15 barely obvious with rounded and pointed tubercles.

Spines: Usually carries 3 spines, but sometime 5 or 7.

Flowers: Whitish to rose pink, deepening to purple in the centre.

Remarks: Seems to be a pretty variable plant you might get some other names which are effectively the same plant.... and also not sure all plants identified as this are really this.

Growth rate: It is a relatively slowly growing but easily flowering species.

Soils: It likes very porous standard cactus mix soil. Prefer a low pH compost, avoid substrata rich in limestone; otherwise growth will stop altogether.

Repotting: This plant needs plenty of space for its roots, repotting should be done every other year or when the it has outgrown its pot. Use pot with good drainage.

Watering: Needs moderate to copious waterings in summer, but do not overwater (Rot prone), keep dry in winter at a minimum temperature of 0°C.

Fertilization: Feed with a high potassium fertilizer in summer.

Hardiness: Reputedly resistant to frost if kept on the dry side prior to, and during, cold weather (hardy to -5 C° C, or less for short periods).

Exposition: The plant tolerates extremely bright situations but enjoys filtered sunlight or afternoon shade, inside it needs bright light, and some direct sun. Tends to bronze in strong light, which encourages flowering and heavy spine production, but is likely to suffer from sun scorch or stunted growth if over exposed to direct sunlight during the hottest part of the day in summer.

Uses: It is an excellent plant for container growing. It always looks good and stays small. It look fine in a cold greenhouse and frame or outdoor in a rockery.