Grow and Care for Fairy Castle Cactus

Grow fairy castle cactus in full sun and cactus mix that dries. Fairy castle cactus is Acanthocereus. Shops also say triangle cactus for the sprawling species. It is not a flattened night-blooming cereus.

Give it full sun, mix that dries, and a dry winter

fairy castle cactus is a cluster of turret stems with ridges and spines. Give it full sun and mix that dries. Outdoors that means an open, bright spot. Indoors, set the pot at a bright south or west window. A plant that just left a shaded greenhouse will scorch if you set it against hot glass on the first day, so move it into strong sun over about two weeks. [1] Water when the mix is dry in the growing season. In winter, keep it cool and dry.

1. Site it in full sun outdoors, or at a south or west window indoors. A dim room stretches the turrets and they flop.
2. Use cactus mix with grit. Ordinary potting soil holds water against the roots.
3. Soak until water runs out, then wait until the mix is dry. Empty the saucer. Skip extra water in cool, low light.
4. In winter, keep the pot cool and dry. That rest keeps the stems firm — not a warm, wet sill.

Plant it in a pot with a hole, or draining ground if frost stays off

In most of the US, grow it in an unglazed pot with a hole so you can bring it in before a freeze. Where frost stays off, you can plant it in a sunny bed that drains. [2]

1. Wear gloves before you lift it. The ridges carry spines, and a turret can snap at the joint.
2. Choose a snug pot about an inch wider than the root mass, with a hole. A pot that is much larger stays wet around the roots.
3. Set the plant at the same depth it grew in the nursery pot. Do not bury the green tissue.
4. If you plant in the ground, use a bed that dries after rain. If the native soil holds water, mound it or backfill with cactus mix.
5. Wait about a week after you plant or pot it before the first soak, so broken roots can dry. Then soak once, and wait until the mix is dry again.
6. Bring a pot in before a freeze. Set it where it will not get knocked, because a bump can break a turret.

Cut a turret and let the wound dry before you set it

You do not prune this cactus to reshape it. A nursery plant is the usual start. If you want a second plant, cut a firm turret in warm weather and let the wound dry so it does not rot in the mix. Old stems turn woody at the base as they age. That corking is normal. You do not need to cut it off.

1. Wear gloves. Cut a firm turret two to four inches long in late spring or summer, when the plant is growing. Cut cleanly at the joint.
2. Set the cutting in a dry, shaded spot until the wound skins over. About a week is enough on a typical turret.
3. Set it upright in cactus mix that drains, and bury only enough of the base to hold it. Do not water for about a week.
4. Then soak once, and wait until the mix is dry. Keep it in bright light until you feel resistance on a gentle tug, then move it into full sun.

Not a night-blooming cereus — and not Christmas cactus

Night-blooming cereus on a tag is usually a climbing dragon fruit vine or a flattened orchid cactus. fairy castle cactus is a cluster of turret stems. Confirm the Latin. Acanthocereus is not Selenicereus. See How to Grow Dragon Fruit if the plant in the pot is a climbing, three-angled vine, or How to Grow Orchid Cactus if the stems are flat and leaf-like. [3]

The wild triangle cactus, also called barbed-wire cactus, is the same species as this cultivar. It sprawls on sharply three-angled stems and opens large white flowers at night. Fairy castle cactus in a pot almost never does that. A sprawling coastal plant with three ridges is the species, not the turret cluster. [4] Christmas cactus is a flattened holiday stem — see How to Grow Christmas Cactus if that is the plant you have. It wants more water than this cactus.

When the mix is dry and the turrets look plump, soak once. If frost is coming, bring the pot in.