The only way you get to see these cacti flowering is if you are extremely lucky. They don't flower on schedule, and flowers are open for one day only. This year (second time in 25 years) I got lucky. Echinocactus horizonthalonius var. nicholii. https://t.co/wDXYiAulKt

— Dr. Margrit McIntosh (@memcinto) 2021.7.25

@BeesBackyard Hi, Echinocactus horizonthalonius var nicholii blooms whenever it damn feels like it and good luck catching it as they mass bloom and the flowers are only open one day. (But they can bloom multiple times a year.) Usually July tho.

— Dr. Margrit McIntosh (@memcinto) 2019.4.4