With Christmas and Hanukkah just around the corner, our Environmental Gardener columnists Greg Levine and Erica Glasener collaborated on this gift guide for gardeners. Bluestone Perennials We both find that as we get older it can be challenging to buy gifts for friends and family who don’t really need anything. But for our friends that are gardeners or lovers of plants, we have a range of gift suggestions.  A Living Present Erica’s Pick:  It’s hard to go wrong with a living arrangement in a beautiful decorative pot, whether it’s a simple phalaenopsis orchid for indoors (almost foolproof), or a container garden for the patio with winter blooms. Try including violas,…