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