Neville helped Professor Sprout restore the greenhouses to their former glory after the war and never left so that when she retired a couple of years later he took over as head of Herbology. However, he did take a couple of years sabbatical to travel and collect rare plants from around the world later on.
“Oh look at the time,” Louis says quickly, turning on his heel and rushing to the greenhouse door. He twists the handle and tugs on it a few times, yanking progressively harder. “Oi, Harry, if you’re the president, then you’re in charge of this shack, right? So why won’t the fucking door open?”
Harry carefully steps over the mess on the ground and heads to the door, giving the handle a twist and pulling as hard as he can. It’s a futile attempt because the door doesn’t budge, not that Harry thought it would. There’s no way Louis would have known to be careful with the door, and with the wind howling outside right now, shutting it gently would be near-impossible.
“It’s shut,” Harry says, giving it a final, firm yank. The door doesn’t move an inch.