I didn't get round to talking about many plants (in the aforementioned post, published by Gardenista) but the following have been linked with one or both of them and once these It Plants have been remarked on, you'll notice them in all the right places.
Above: our reporter goes incognito at Cottesbrooke Hall, Northamptonshire.
Aster divaraticus, spotted at Beth Chatto's last September, comes highly recommended by Chris Marchant. It doesn't get too tall, it doesn't flop, it's a kind of ground cover, it has dark stems and a fresh foliage when other plants are looking a bit haggard. It's an It plant.