Being in the moment is a challenge in our busy, too-connected age, yet it is essential for appreciating and understanding the garden.   Poet Susan Brearley shares her practice for mindfulness: the on-the-spot composition of garden haiku.  Brearley, who has been teaching haiku workshops at the great Innisfree garden in Millbrook, New York, shares the basics of this classic Japanese poetic form, along with a look at the sensibility that traditionally informs it.