Hooray for the urban heat island

Begonias, in for the evening

Last night, I piled some of my begonias into a plant tray and brought them indoors for safekeeping.  There was a forecast of near-freezing temperatures and near-certainty of frost, but this time of year I always gamble a bit, bringing in just my most tender or irreplaceable plants, and leaving the rest to their fates.  We may be well into November but I'm not quite ready yet for the annual routine of lugging potted plants in, and putting sheets over the plants I can't bring in, every time a frost is predicted.  It's just too damn much work (have I mentioned before how lazy I am?).

Duration, duration, duration

Garden at the end of January

When I give talks about growing hardy palms or other marginally hardy plants, one of my talking points is "location, location, location".  My point is that I live in a city, so I benefit from an urban heat island that keeps me quite a bit warmer than the surrounding suburbs.  In addition, there are microclimates within the city, and even within our own yards, that can add or subtract up to a half zone of hardiness.  For example, my property is on a north-facing slope that receives no direct sun from mid-November to mid-January; overnight low temperatures in my yard are nearly always several degrees colder than the "official" temperatures for Washington, DC as recorded at Washington National Airport (which, ironically, is not even in DC!).  This morning the official low at DCA was 16 degrees, but at 4:00 am the temperature in my yard was 12 degrees.