Holiday horticulture tends to revolve around the same handful of plants. So if you don’t already have any or all of these five holiday plants, now is the time to get them: PAPERWHITES The bulbs of these daffodil family members are pre-chilled so they can be planted now and produce flowers in a month to six weeks. If you find them for sale, by all means buy as many as you can. The only caveat is that some family members may object to the unbelievably sweet smell of their blooms. POINSETTIAS Poinsettias, of course, are for sale in all manner...