What is the collective noun for flax?

There isn't a widely accepted collective noun specifically for flax.

However, you could use more general terms like:

* A stand of flax

* A patch of flax

* A field of flax

* A crop of flax

You could also use the word "growth" or "harvest" to indicate a large amount of flax.

Ultimately, the best way to describe a collection of flax depends on the context.