Blue candle cactus care guide

Myrtillocactus geometrizans

Also known as: Bilberry cactus, Myrtillocactus geometrizans 'Fukurokuryuzinboku'

Cacti
Care level: Moderate

Pets and children

Caution advised

The ribs carry hard spines that can injure a pet's mouth or paws; keep it out of reach and see a veterinarian (or a doctor, for a child) if a piece is eaten or a spine sticks.

How often to water Blue candle cactus

Spring–Summer (Mar–Sep): Every 10 days; A summer grower: as a guide, water thoroughly two or three days after the soil has dried all the way through.
Autumn (Oct–Nov): Every 14 days; Stretch the gaps as it cools, watering about a week after the soil dries, as a guide.
Winter (Dec–Feb): Every 30 days; Keep it nearly dry, moistening the soil lightly about once a month on a warm morning.

Light and placement for Blue candle cactus

Generally happiest outdoors in full sun with good airflow, under the eaves out of the rain; harden it off before midsummer sun, which can scorch the blue skin, and too little light makes the stems thin and misshapen.

Overwintering Blue candle cactus

Overwintering guide: 5°C (41°F) or above

Somewhat cold-sensitive: as a guide, move it to a bright window indoors before nights drop below about 5°C, and keep it nearly dry so the cold does less harm.

Fertilizing and repotting Blue candle cactus

Fertilizer

Diluted liquid feed about once a month from April to September; it grows fast, so overfeeding makes soft, stretched growth, and none in winter.

When to repot

Spring–Summer (Mar–Sep)

Common problems with Blue candle cactus

In a dim room the new growth comes out thin, leaving a lopsided plant.
Watered through winter, it rots from the base.
Moved straight into spring sun, the skin scorches and the brown marks stay.

Tips for growing Blue candle cactus

Vigorous enough to serve as grafting stock, it drinks readily in the growing season.
It grows quickly, so repot every year or two before it becomes root-bound.
The monstrose Fukuroku form takes the same care but keeps its shape better when grown a little drier.

These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.

Keep your plant log going

Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.

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