Troubleshooting
Mexican Pincushion problems — and how to fix them
Mexican Pincushion (Mammillaria magnimamma) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Root rot
Poor drainage or overwatering causes the base to rot. Use a gritty mix, a pot with drainage holes, and avoid watering in cold weather.
Mealybugs
White cottony deposits between tubercles indicate mealybugs. Treat with isopropyl alcohol on a cotton swab or a neem oil spray.
Scale insects
Small brown lumps on the stems can be scale. Remove manually and treat with insecticidal soap or horticultural oil.
Etiolation
Stretching and pallor in the stems indicate insufficient light. Gradually move to a sunnier position.
Red spider mite
In hot, dry indoor conditions, fine webbing and stippling may appear. Improve ventilation and treat with an appropriate miticide if necessary.
Prevent mexican pincushion problems before they start
Most mexican pincushion issues are care-mismatch, not bad luck. Dial in the basics:
Mexican Pincushion problems — FAQ
Why is my mexican pincushion root rot?
Poor drainage or overwatering causes the base to rot. Use a gritty mix, a pot with drainage holes, and avoid watering in cold weather.
Why is my mexican pincushion mealybugs?
White cottony deposits between tubercles indicate mealybugs. Treat with isopropyl alcohol on a cotton swab or a neem oil spray.
Why is my mexican pincushion scale insects?
Small brown lumps on the stems can be scale. Remove manually and treat with insecticidal soap or horticultural oil.
Why is my mexican pincushion etiolation?
Stretching and pallor in the stems indicate insufficient light. Gradually move to a sunnier position.
Why is my mexican pincushion red spider mite?
In hot, dry indoor conditions, fine webbing and stippling may appear. Improve ventilation and treat with an appropriate miticide if necessary.