So I've just finished planting this yew hedge in a box and am thinking about laying some drip hose to water it. It occurred to me that I ought to have buried the hose before planting. I'm in bergen, Norway so too much rain is normally the problem! I'd like to train the hedge outward so all the soil is covered, but I guess this'll drastically reduce the amount of rain getting into the plant. Does it make any difference to bury the hose for a hedge like this, or is surface irrigation sufficient enough?