never
Euphorbia is a highly diverse plant genus, comprising some 5,000 currently accepted taxa.
Source (for the butt)?
https://twitter.com/lunarclaws/status/955100668381057024
"Euphorbias range from tiny annual plants to large and long-lived trees. with perhaps the tallest being Euphorbia ampliphylla at 30 m (98 ft) or more. The genus has roughly 2,000 members, making it one of the largest genera of flowering plants."
just the other day i discovered that my "cactus" is in fact a euphorbia trigona, and they can grow into TREES, so i guess i have a lifelong companion.
My favourite Euphorbia