Trimming Plants at top instead of roots

Hey guys, I was just wondering if I could trim these plants by cutting the top of it instead of trimming by the roots, because I find them a little too high. I am not sure either what's the type of these plants because I asked the guy at the store and he didn't even know -_-. Thanks already !

 

The plants are hornworth. They can be trimmed any way you please. The trimmed pieces can be left floating or planted and they will regrow.

 

Okay thank you !

 

Not hornwort actually the are cambomba. You can trim anywhere you like and replant the trimming

 

+1 to the cambomba, I don't think it looks like hornwort

 

Oh okay! Thanks guys! Those plants grow so fast it's insane haha!