The name was explained by the following dialog in Episode 1:
Annalee Cannon: Isn't it beautiful, John? It should have a name.
Big John Cannon: You name it.
Annalee Cannon: What is that bush called — that green one?
Big John Cannon: Chaparral.
Annalee Cannon: That's it — Chaparral. I christen thee "The High Chaparral" — the greatest cattle ranch in the whole territory ... the whole world!
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California Peninsula, Mexico. The name comes from the Spanish word for scrub oak, chaparro.