Fancy orchids (see above) or camelias ? Then head to the Lyman Estate Greenhouses in Waltham, with greenhouses chock full of blooms. Some are available for sale, as well.
It's not too late to take in the Christmas lights at Tower Hill Botanic Gardens in Boylston MA. Just get there before January 4. There's more to see than just the lights, like, say the Orangerie.
While you're in that part of the state, take a brief detour to Clinton and the Museum of Russian Icons, and walk a couple of blocks to have a nosh -- say, coffee and some kattayif or baklava -- at Zaytoon, 72 High Street.