I thought the name sounded familiar.
A post from October 2018
Thevetia peruviana, sometimes called Yellow Oleander
This stamp was issued by Vietnam in 1977 in an eight stamp series named WILD FLOWERS.
Apparently, as with, Oleander it is very poisonous.
Thevetia peruviana is mentioned several times in THE MEDITERRANEAN GARDEN
I have chosen issue number 30, October 2002 for you to read today
SPAROZA IN SUMMER by Caroline Harbouri