Benefit plant sales are a traditional spring event. Gardeners can spruce up their gardens and benefit various community organizations. Which will you choose? Or will you choose them all? Have you thought about giving your mother a gift certificate (one way or another) so she can pick out  some flowers herself? This Saturday, May5 the Greenfield Library will open its plant sale at 9:30 am on the front lawn. It will close by 12:30, unless everything is gone…