The serrano pepper is a type of chili pepper that originated in the mountainous regions of the Mexican states of Puebla and Hidalgo. The name of the pepper is a reference to the mountains (sierras) of these regions. They rank hotter than a jalapeno.
The Scoville rating of the serrano is 10,00 to 23,000 which puts it in the moderately spicy category, particularly relative to the ratings of increasing popularity of peppers such as Ghost and Carolina Reaper.
The plant can grow to 18 to as much as 60" tall in the best conditions.
The fruit can be harvested green or ripe---ripened colors can vary but are often red.
Serranos are the second most used chili pepper in Mexican cuisine.