Can Vallisneria plants be trimmed?

Calmwaters

I ordered a plant package from a seller on aquabid for my 20 gallon long tank and they are very nice plants but three of them will get to tall for my 20 gallon one is a flame sword and the other two are Jungle Valliseria and Italian Valliseria. I really like the way the tank looked with these plants in it so I am wondering if it would be okay for the flame sword leaves to float across the top of the tank and for me to trim the vals or will they only grow the height of the tank?

zof

All my jungle vals died, but my leopard Italian vals once established need regular trimming as they will get to the top then keep growing along the water line in all directions as they are not strong enough to grow out of the water. I trim them about every 2 weeks or so at the top from where they grow and get long peices all the time that are about a foot long.

No clue about the sword as the best one I have right now is only about 2/3rds up the tank but its still getting bigger and bigger every month.

Calmwaters

I think I have decided I am going to just put them in the 55 gallon they will look nice there and will have a good bit of room to grow. Thank you for your help.