Gymnocalycium denudatum cv. Jan Suba

🌵 Care Guide

Gymnocalycium denudatum cv. Jan Suba is a beautiful and distinctive cultivated form, believed to be a hybrid involving Gymnocalycium denudatum and Gymnocalycium baldianum. It is admired for its glossy dark-green, rounded body, delicate pale spines, and especially its large, vibrant pink to deep magenta-red flowers.

☀️ Light

• Prefers bright, filtered light to partial sun.
• Morning sunlight is beneficial, while intense afternoon sunlight should be filtered during hot summer weather.
• Indoors, place it near a bright east or south-facing window with some gentle direct sunlight.
• Too much intense direct sunlight can cause sun stress or scorching, while good light encourages flowering and healthy spine development.

💧 Watering

• Spring & Summer: Water thoroughly when the soil is completely dry.
• Allow excess water to drain completely before watering again.
• Winter: Reduce watering significantly and keep the plant relatively dry during its resting period.
• ⚠️ Avoid overwatering, as Gymnocalycium can be susceptible to root rot when kept in constantly wet soil.

🌡️ Temperature

• Prefers warm temperatures during its active summer growing season.
• Can tolerate cooler conditions when kept dry.
• Protect from prolonged freezing temperatures for safer cultivation.

🌱 Soil

• Requires a very porous, fast-draining cactus soil mix.
• A slightly acidic to low-pH growing medium is preferred.
• Avoid substrates that are excessively rich in limestone, as unsuitable soil can restrict growth.
• Adding pumice, perlite, or coarse sand can further improve drainage.

🍽️ Fertilizer

• Feed during the summer growing season with a diluted cactus fertilizer.
• A fertilizer with relatively higher potassium can support flowering and healthy growth.
• Reduce or stop fertilizing during the winter resting period.

🪴 Potting

• Use a pot with excellent drainage holes.
• Provide enough space for the roots without using an excessively large container.
• Repot approximately every 2 years or whenever the plant outgrows its pot.
• It remains relatively small and is well suited to container growing.

🌸 Flowering

• Produces large, attractive pink to deep magenta-red flowers.
• Flowers can reach approximately 5 cm in length and 7 cm in width.
• Flowering generally occurs during spring and summer.
• Bright filtered light, proper watering, and good seasonal care can encourage reliable flowering.

🌵 Appearance

• Usually remains solitary with a broadly globular to slightly flattened body.
• Features a glossy greyish-green to dark-green body with broad, low ribs.
• Its pale white to pinkish, curved radial spines lie close to the body and create a delicate appearance.