All foot long plecs will have issues with knocking plants over, their body shape and the way they move makes it very difficult for them to get around in a planted tank as they like to be able to swim fast from one end of the tank to the other every now and then- i find with my plecs, they have no issues at all with the plants though...
If you only plant/decorate 50% of the tank, and leave the sides of the tank open with the main bulk of open space being at the front of the tank, you will find the plecs will avoid the planted areas as long as they have these open swim-ways around the tank for them to use. When it comes to down to it, you cant expect them to just stay in one end of the tank all the time, so its best it you decorate the tank allowing them to use the sides of the tank as well as the back and front- when it comes down to it they dont pull plants up for fun and they dont like getting tangled/caught up in plants- if you observe many plecs natural habitats, you will find they prefer to occupy the open areas rather than densely planted ones- this is also how they have evolved to live.