There are a bunch of different types of vals. The ones JR and i have are jungle and spiral. The spirals just grow about 6-8" and spread like weeds and the jungle grow 3-4 FEET and spread like weeds. JR has it right just snip at what ever height you want at a 45° angle. I tend to snip them at the base because the get too thick and spread too much. Last week I threw away almost 20 jungle vals that were no less than 2feet long.