Q.why are there no catkins on the cattails this year?
Cattails are growing wherever they have been before, but none of them have catkins, just the plants. This is in ND and SD.

Cattails are directly impacted by environmental conditions.
Water, temperatures and wind will effect the plants.
Last year the cattails were thin here, and this year the cattails are quite abundant. I am in Souther MN, we have had quite a bit of heavy wet weather.
https://www.gardeningknowhow.com/ornamental/water-plants/cattails/controlling-cattails.htm
http://www.cattails.info/Types_of_cattail.html