After keeping this cactus as a houseplant for 4 years, it surprised me by blooming last July. I was lucky to be home as the bloom lasted for just 1 day. Does anyone know what kind of cactus this is?
An Echinopsis, of which there are numerous kinds. It will likely bloom more for you in future years. Give a lot of sun in the spring and summer, keep it cool and dry in the winter.
I would say it's some species of Trichocereus (spachianus, perhaps?).
Was it fragrant? It's very beautiful - congrats!
I thought the fragrance was similar to an oriental lily. The petals were of a similar texture of a peony.