Pocket BotanistPlant guide
Old man cactus.
Cephalocereus senilis
Pronounced sef-uh-loh-SEE-ree-us sen-IL-iss
Also known as bunny cactus, old man of Mexico, old-man cactus, white Persian-cat cactus, Old Man Cactus
The old man cactus is a striking succulent known for its long, shaggy white hairs that cover its columnar body. It grows quite slowly and brings a unique, fuzzy texture to any sunny collection. You will love how those silver locks catch the light in a bright window.
At a glance
- Care level
- Moderate
- Plant type
- Succulent
- Light
- Full sun
- Indoor light
- Direct sun
- Water
- Every 14 to 30 days
- Mature size
- 15 to 20 feet in habitat
- Growth rate
- Slow
Care
Keep this cactus in a spot with plenty of direct sun to maintain its dense hair growth. Watch for signs of rot like mushy stems, which usually happen if the soil stays damp for too long. Use a well draining cactus mix to keep the roots happy and dry.
- Watering
- Allow the soil to dry out completely between waterings to prevent root rot.
- Feeding
- Feed with a balanced cactus fertilizer during the active growing season.
- Pruning
- Pruning is rarely needed, but you can remove dead or damaged sections with clean shears.
- Repotting
- Repot only when the plant becomes rootbound, as it prefers to stay in a snug container.
- Soil
- Sandy, well draining cactus mix
- Soil pH
- 6.0 to 7.5
Safety
- Pets
- This plant is generally considered non-toxic to cats and dogs.
How to identify it
- Columnar stem covered in white hair
- Sharp yellow spines hidden under hair
- Slow growing cylindrical body
- Dense woolly growth at the crown
Science
- Family
- Cactaceae
- Genus
- Cephalocereus
- Order
- Caryophyllales
- Class
- Magnoliopsida
Taxonomy resolved against GBIF.
Is your old man cactus looking unwell?
This page is a general guide. Pocket Botanist diagnoses problems from a photo of your actual plant, works out watering for your light and conditions, and reminds you when care is due.
This guide was generated with AI and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.