Old lady cactus

Old lady cactus key facts

Growing Difficulty

Beginner-friendly

Lifespan

Perennial (little published data on lifespan)

Size

Stems about 9 cm tall and 10 cm across; clumps may reach about 50 cm wide

Watering

A little potassium-rich fertiliser in summer

Light & Placement

It likes sun: outdoors give full sun or afternoon shade, and indoors a bright spot with some direct sun.

Watering

Cacti are grown much like summer-growing succulents. Water regularly in summer but avoid overwatering, as it rots easily; keep it dry in winter.

Temperature & Overwintering

Kept dry it is fairly cold-tolerant, reportedly to about -5°C, but in frost-prone areas winter it indoors or in a frame.

Soil & Repotting

Use a very porous mix in a well-drained pot, and allow room for it to spread into a clump.

Propagation

Propagate by dividing clumps or from seed.

Pests & Cautions

It rots easily when overwatered, so keep it somewhere airy where the soil dries quickly. It grows fast and clumps, so give it plenty of space.

About Old lady cactus

Old lady cactus (Gyokuo): a round Mammillaria wrapped in long white hairs, with rings of reddish-purple flowers even when young. A beginner-friendly perennial.

7 things to know before growing Old lady cactus

1. 1Bright light and airflow

   From spring to autumn, give it a bright spot outdoors or a sunny windowsill. With too little light the plant stretches and the white coat and flowering both suffer. Strong midsummer sun can scorch the body, so moving it to bright partial shade is safer.

2. 2Water only when dry

   Wait until the soil is dry, then water thoroughly until it runs out of the drainage hole. Wet hairs dry slowly and can cause rot, so pour onto the soil near the pot rim instead of over the plant. Even in the growing season, err on the side of watering less often.

3. 3Fast-draining soil

   A cactus and succulent mix, or a blend with plenty of akadama or pumice, suits it well. Choose a pot with a drainage hole that is only slightly larger than the plant to avoid soggy soil.

4. 4When and how to repot

   Repot in spring or autumn, when growth picks up, once the roots fill the pot. Hold off watering for a few days afterward so any damaged roots can dry, then resume as usual. Fine spines lie beneath the hairs, so handle the plant with thick gloves or a folded newspaper wrapped around it.

5. 5Seasonal care

   Treat it like a summer-growing succulent. Water regularly during the summer growing season, but it rots easily if kept too wet, so don't overdo it and keep it somewhere airy so the soil dries quickly after watering. In winter keep it dry, and where frost occurs, move it indoors or to a simple greenhouse in a bright spot.

6. 6Encouraging flowers

   Young plants already flower readily, forming a ring of reddish-purple blooms around the crown. To improve flowering, give plenty of sun and let the plant rest with little water in winter.

7. 7Choosing a plant

   Look for an evenly dense white coat, a firm base, and no discoloration, soft spots or blackening. A plant with offsets offers the fun of growing it into a clump. Check the size and condition in the listing photos and description, and ask the grower if anything is unclear.

Frequently asked questions about Old lady cactus

Q.Can a beginner grow an old lady cactus?

A.Yes, it is rated beginner-friendly. Keep it in a bright, airy spot and water only once the soil has dried, and it is easy to manage. The main thing to watch for is rot from overwatering.

Q.Is it a problem if the white hairs get wet?

A.A little water will not kill it, but hairs that stay wet can lead to rot. Water the soil near the pot rim rather than over the plant, and let it dry in a well-ventilated place.

Q.Why is my plant not flowering?

A.Common causes are too little light or winter care that does not suit it. Give it plenty of sun and rest it with little water in winter, and it is more likely to produce a ring of flowers around the crown.

Q.How large does an old lady cactus grow?

A.The stem grows to about 9 cm tall and 10 cm across. If it forms a clump with offsets, it can spread to around 50 cm wide. For a clumping plant, choose a roomier pot each time you repot.

Q.Can I propagate it from offsets?

A.It forms clumps, so offsets can be separated to make new plants. Remove one with a clean blade or tweezers, let the cut dry for a few days, then set it on dry soil to root. Wear gloves and watch out for the spines.

Handy Growing Tools for Old lady cactus

Learn more about Old lady cactus in the encyclopedia

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