My mum and I have been having the same argument for about twenty years. It goes like this. I say I love the yellow cosmos in our compound because those hot little suns add instant cheer wherever they can be seen. Or our nasturtiums, climbing wild over everything, huge weird-shaped peppery leaves and orange trumpets spilling out everywhere. I think they're glorious. She looks at them, and says, "That's a weed." And every time I want to ask the same, irritated question: says wh