Espostoa senilis

Natural range of Espostoa senilis

Espostoa senilis is native only to Peru. In Ancash and La Libertad it grows in dry Andean vegetation at elevations around 2,000–2,500 m.

Indoor care for Espostoa senilis

• Light: Keep the cactus in a very bright position and introduce direct sun gradually after any period in lower light.
• Temperature: Keep temperatures around 18–30 °C. Avoid prolonged temperatures below 5 °C. Keep the plant warm while it is growing. When growth slows, keep it bright and much drier, with temperatures staying above freezing.
• Humidity and airflow: Aim for 40–50% humidity. Average room humidity is suitable. Gentle air movement helps the long hairs dry promptly after splashes or watering.
• Water: During warm growth, soak the mix and wait until it has dried almost or fully through before watering again. Leave much longer between waterings as growth slows.
• Potting mix: Use a gritty, fast-draining cactus mix with plenty of air around the roots.
• Feeding: Apply a dilute cactus fertiliser every 4–6 weeks while new growth is appearing at the top.
• Potting and repotting: Use a stable pot with a drainage hole as the columns gain height. Repot when roots fill the pot or the mix becomes compacted.

Common problems with Espostoa senilis

• The hairs become wet and matted over a soft patch: Water is being held against the stem by the long hairs. Let them dry, increase ventilation and check the tissue underneath before watering again.
• New growth becomes weak, pale or unusually narrow: Light is too low. Increase exposure gradually and keep the cactus in a brighter position.
• The base softens or darkens: Wet soil during cool or slow growth has caused root or stem rot. Cut decayed tissue back to firm healthy growth with a clean tool and discard the rot. If healthy base tissue and roots remain after the rot is removed, let them dry fully before repotting in fresh mix.
• Cottony insects appear among the hairs: Mealybugs may be hiding between the ribs. Isolate the cactus, inspect beneath the hairs and use a treatment labelled for mealybugs, repeating according to the product label.

Espostoa senilis has sharp parts

• Keep this plant away from children and pets because its effects after chewing or swallowing are unclear.
• Sharp spines can puncture the mouth, eyes, skin or paws.
• Handle it carefully. Contact a veterinarian or medical professional after a serious injury, especially to the eye.

Where does the name Espostoa senilis come from?

Espostoa honours Nicolás E. Esposto. Senilis means ‘aged’ or ‘old’ in Latin and refers to the conspicuous white hair covering.

Nathaniel Lord Britton and Joseph Nelson Rose established the genus Espostoa in 1920 in The Cactaceae, volume 2, page 60.

Friedrich Ritter first described it as Thrixanthocereus senilis in 1961 in Kakteen und andere Sukkulenten, volume 12, page 89. Nigel Paul Taylor later placed it in Espostoa as Espostoa senilis in 1978 in Cactus and Succulent Journal of Great Britain, volume 40, page 54.