Little artist

My girls just love adding their own little touch to things, Not so much Issy anymore but if there's a pen/pencil or crayon to hand Daisie will have a little doodle, As cute as it is that shes getting all arty I'd much rather it was on some paper and not her bedroom walls, my new tv cabinet or my freshly painted living room walls :(
So a fresh lick of paint in the girls room is on the cards and I have to tackle getting the drawings off the wallpaper and find something to cover the bit Daisie ripped off. I have plans to wallpaper another wall but while she's at this little artist stage I'm wondering if it's even worth bothering with for now.
I also have plans of spraying/painting a part of their wall with blackboard paint Andy will be giving it a wooden boarder but I'm still torn will they stick to that part or will they think it's okay to draw on the other walls too because they are on that one? I just don't know but I'm hoping the fact it has a wooden boarder it will look like I've stuck an isle to the wall :) Time shall tell