You can, but remember that any plant does not stop growing at a certain height. When the conifers get to a required height, they must be trimmed annualy and even then you must expect an increase in height even if its only two inches. (You cant cut into old wood you see or it will be just twigs!. Watering is your biggest problem with these. If they dry out they drop greenery and again will go brown and they dont recover lost greenery. These conifers are cheap to buy (�1.50 each?), so I would plan on replacing them after so many years and starting again.