Neville nodded in agreement with Sirius' logic. He had been trying this common sense approach - unfortunately without much success - at the nursery.
Swallowing down his nerves at speaking up in front of so many of the people he admired, he tightened his hold on Luna's hand and said, "If we're starting with what's wrong, it's not just Wizard's magic that's affected. Spells, charmed objects and potions come from our magic, human magic, but the plants at my nursery have been behaving oddly, too. It looks like it's all magic that's been thrown out of sync. I don't know what that means, but it might rule out some of the possible causes."