The night-blooming cereus flowers once a year, and, for the best performance in town, Tohono Chul Park is the place to be. The park, at 7366 N. Paseo del Norte, has more than 350 of the native cactus on its grounds, the largest collection in the world, Tohono Chul communications coordinator Glenn Nowak said.”They’re starting to open now. You can see them starting to show a little color,” Nowak said around 4:30 p.m.

Peniocereus greggii, the night-blooming cereus

Wow.