What's the plural form of napiergrass? Here's the word you're looking for.
Answer
The noun napiergrass can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be napiergrass.
However, in more specific contexts, the plural form can also be napiergrasses e.g. in reference to various types of napiergrasses
or a collection of napiergrasses.