Gymnocalycium Horstii (Spider Cactus)

Gymnocalycium horstii
Common Name: Spider Cactus

Gymnocalycium horstii, commonly known as the Spider Cactus, is a uniquely beautiful globular species native to southern Brazil. This cactus is instantly recognizable for its glossy, rounded body and dramatically curved white to pale yellow spines that arch outward like a spider's legs—earning it its nickname.

The plant’s deep green body stays compact and can eventually form small clusters. During spring and summer, it puts on a show with large, silky white to pale pink blooms that emerge from the crown—often bigger than the plant itself! It's an easy grower and a great introduction to the Gymnocalycium genus.

☀ Light Requirements
Prefers bright, indirect sunlight or filtered light. It can tolerate some direct sun, especially in the morning, but avoid harsh afternoon rays that can scorch its skin.

💧 Watering Needs
Water thoroughly only when the soil is fully dry. Use a fast-draining cactus mix and reduce watering in the winter. Very sensitive to overwatering—less is more.

🌡 Temperature Tolerance
Hardy down to around 30°F in dry conditions. Protect from frost and excessive cold. Add a [Heat Pack] when shipping in winter or cold zones.

✨ Special Features
• Glossy, Rounded Form – Deep green body with a clean, sculptural look
• Curved “Spider” Spines – Unique arched spines give it a dramatic silhouette
• Eye-Catching Flowers – Large, soft blooms that contrast beautifully with the body

Other Common Names:
Spider Cactus, Horst’s Gymnocalycium

This cactus will ship bare root and will be ready to place directly in a well draining soil mix like our Custom Cactus Mix.

Photos in the listings unless otherwise specified are representative of the plant that will be sent to you.
However, Plants grow differently and each plant may vary slightly in shape, size, growth pattern, etc.
Of course, if you receive a plant that you are dissatisfied with please reach out to us. We want to make it right!

If temperatures near you are below 45℉ we highly recommend adding a Heat Pack to your order.
If temperatures where you live will be much lower than 20℉ even heat packs may not work. You may consider waiting until things warm up a bit. We know you love your plants just like we do and we wouldn't want any of them to freeze.