The second-best time is now - and so I planted a number of trees which will eventually transform Riverbend into a park with shady spots and sunfilled corners.
Some of the trees I planted are a native rainforest tree called Tuckeroo (a.k.a. cupaniopsis anarcardioides, but, of course, you knew that already ☺), the NZ Christmas Tree or Pohutukawa, several flowering ashes, a small-leaved fig tree which will grow to 40 metres, weeping lilly pillies (waterhousea floribunda), several Australian frangipani trees, a Cape Virgilia, and some silver birches to remind me of the (c)old country.
I won't see them grown up because, as I said, the best time to plant them was twenty years ago but the second-best time is now.