The first plants to show green in my garden are the herbs growing right in front of my piazza.  Parsley, sage, rosemary and thyme – as well as dill, tarragon, chives, basil, lemon balm and black stem mint – are handy for seasoning my cooking, and for steeping a cup of tea. Other herbs are planted throughout the garden: black cohosh or cimicifuga racemosa; comfrey; scented geraniums, and lovage. Herbs fall into two main categories. It is the…