Chirimoya, LOL this is a very tolerant plant. They can be invasive, and don't mind a bit of a drought.
This plant is called Catharanthus Roseus or commonly named vinca rosea. Don't be fooled it is not vinca minor/ major. That specific plant is a ground cover.
The Catharanthus Roseus can be hallucinigenic....jeez, I have a lot of plants that can literally blow your mind
This "madagascar periwinkle" is loaded with alkaloids, which have been used in anticancer drugs. Also, when injected will suppress blood vessels that tumors need to thrive.
In India it is used to treat wasp stings (leaves).
In Hawaii it's boiled for a poultice to stop bleeding.
In China and Central/ South America it's used for a cough suppressant.
In the Caribbean it's flowers are know to help eye infections.
In Jamaica it's used as a tea for diabetes.
This plant has many uses and it's pretty, flowering most of the year.
The alkaloids (very high in nitrogen), reserpine and serpentine specifically are tranquilizers that are strong.
Some side effects are nausea and hair loss, so don't go trying to eat this stuff. Also rumored to be harmful to children and animals.
John Evans the flowers are similair to impatiens especially the "walleriana". The stems are sturdier and each stem only puts out one flower, thus when pruned properly it can look like a globe of flowers.....but you already knew that, didn't ya?