What is the collective noun of stalks?

There isn't a widely accepted collective noun for "stalks." However, you could use:

* A stand of stalks (if referring to plants)

* A bunch of stalks (if referring to a bundle of stalks)

* A row of stalks (if referring to a line of stalks)

You could also get creative and use descriptive terms like:

* A thicket of stalks (for a dense collection)

* A swathe of stalks (for a wide, continuous area)

* A cluster of stalks (for a group of stalks close together)

The best collective noun will depend on the context and what you're trying to describe.