Cacti are my favorite houseplant species because they require minimal care. In the springtime after the last frost, I move the plants outdoors to a shaded area. Gradually I move them into the full sun after they become acclimated to the brighter light. 

Before the first frost I bring my cacti inside and place them in a bright window. No care, no water and no hassle.

Most of my cacti came from a friend who was closing a greenhouse. One columnar variety has grown quite tall over the years, reaching almost 5 feet. The term ceroid describe cacti species with very elongated bodies. I learned in 2014 that my ceroid cactus could produced a large night blooming flower. In September of that year I noticed two buds, which opened in the evening.

The flowering came as a complete surprise and in following years I expected a recurrence to no avail. The cactus grew taller and heavier for 4 more years. In Spring of 2018 I lopped off a large chunk of the top and planted it in a pot, propped up with sash weights.  I was hoping that it take root during the summer. Imagine my surprise when I saw a flower bud develop.

There were two buds and one dropped off, but this one survived.

When I got up at midnight, the flower was completely open. It has no fragrance but I assume it is attractive to bats and moths in its native home.