By Nathan Tufts Park the old stone powder house still stands round and blunt against the sky, and the gardens around that corner of the city have been planted and replanted for generations. Gardens by Ruth works in that spirit — mowing and trimming the grass, edging the beds by hand, cutting back perennials and shrubs, laying mulch dark around them so the color has something to sit against. June mornings here are the good ones, dew still on the lawn, the shears making that dry snip. Spring and fall the whole yard gets emptied out and reset, leaves and all. It is patient work, and the result is a small green room in a very dense place.