Thursday, January 30, 2014
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.
Tuesday, January 28, 2014
Scottish Rite Temple, December 2009 (Photo: Kenneth Fletcher)
In summer 2009 an interesting thing happened. The Scottish Rite Temple on 16th Street in Washington, DC--just blocks from where I live--had new landscaping installed that included two good-sized palm trees flanking the front entrance. The palms were palmettos, Sabal palmetto, a species native to the southeastern USA. This had various palm growers scratching our heads; were they meant to be permanent? If so, they were a poor choice as this species isn't hardy in zone 7, and planting so late in the growing season would give them insufficient time to establish themselves before winter. But if they were meant to be temporary plantings, it seemed rather expensive and extravagant.
Sunday, January 26, 2014
Fronds of Trachycarpus wagnerianus after an extended freeze
Things are not looking good in the garden. After several days of temperatures well below freezing, I was hoping for a bit of a thaw this weekend but after an initially promising forecast on Friday was revised downward, and my thermometer read only 30 degrees at 4:00 pm yesterday, I think that's as good as it's going to get. The latest forecast for today is 30 degrees, and 39 degrees tomorrow, but I'll believe it when I see it. Monday will mark a full week of temperatures below freezing.
Monday, January 20, 2014
Nothing to say right now, just a photo of the great sunset I enjoyed from my roof deck this evening. I haven't been blogging for the last week and a half as I've been in Buffalo helping to take care of my father (see my earlier post, "The roots of a gardener"). I hope to get at least one blog post up before our next visit from the dreaded polar vortex.
Friday, January 10, 2014
I took the day off from work yesterday so I could drive to the Baltimore Convention Center for the Mid-Atlantic Nursery Trade Show, MANTS, which bills itself as "The Masterpiece of Trade Shows™", trademark symbol and all. This was my second time attending MANTS, but my first time covering it as a blogger. This is a huge 3-day event, drawing nearly a thousand exhibitors in the nursery and horticulture trade from all over the country and well over 10,000 registered attendees. When I went last year, I was absolutely overwhelmed; I hoped that attending as a blogger would help me narrow my focus a bit as well as give me an excuse to talk to people!
Tuesday, January 7, 2014
Curled leaflets on a Trachycarpus wagnerianus frond at 5.2 degrees
After several days of practically apocalyptic forecasts, I spent last night listening to the wind and wondering just how cold it would get. After a rainy and fairly warm morning, at around 5:00 pm the wind had picked up, the temperature started dropping rapidly, and by this morning, local airports had recorded our area's lowest temperatures since 1996. At 8 am, the official low temperature at DCA (Washington National Airport) was 7° F (-13.9° C) but in my own back yard, the temperature was 5.2° F (-14.9° C), the coldest I've had since buying this property in December 2000. The next coldest I've recorded was 6° F (-14.4° C) in January 2004.
Sunday, January 5, 2014
Begonia bed, August 2013
Begonia bed, January 2014
Somewhere, under the snow, I have begonias. At least I think I do. For the last few years I've been testing a large number of begonia species and hybrids for hardiness, and early results have been very promising: some of them have come through 1, 2, and even 3 winters. But let's face it, the last several winters haven't been a very rigorous test, with the lowest temperature since February 2009 being about 15 degrees and with few extended periods remaining below freezing. But that is all about to change: with a low in the single digits forecast for Monday night, it looks like they will finally be getting that test.
Saturday, January 4, 2014
Palm fronds bending under the weight of snow
Thursday night saw a rapid drop in temperatures accompanied by snow that is still sticking around, including on my palms! The standard advice is to use a broom to gently knock snow and ice off palm fronds to help prevent breakage or other mechanical damage, but I've been going back and forth on whether to do this. My reasoning is that the snow might actually help prevent desiccation from cold winds, especially as temperatures drop the next few days. I could be absolutely wrong, but with lows forecast to go into the single digits last night, I figured the damage was already done and I might as well leave it. As it turns out, the low last night in the city was 18 degrees--several degrees higher than the warmest forecast and certainly nothing to be concerned about--and it's going to warm up enough tomorrow that all the snow will probably melt or fall off on its own anyway. And then comes Monday night! I'm still wondering how my palms will fare if it really goes into the low single digits as they're predicting, but who knows, the urban heat island just might save my ass one more time!
Windmill palm (Trachycarpus fortunei) with snow
Forecast lows for Monday night/Tuesday morning (source: Washington Post)
A few days ago I wrote about a major cold wave pouring south from Canada. The weather forecasters are starting to talk in apocalyptic terms, telling us that this event is likely to give us our lowest temperatures in 20 or maybe even 30 years. A story in yesterday's Washington Post states, "Some of the coldest air in years, if not decades, is poised to pour into the U.S., with mind-boggling low temperatures.... it’s possible all of the I-95 cities from D.C. to New York City drop below zero [= -17.8 C] for the first time in nearly 20 years."
The last time Washington, DC had temperatures like that was February 1994 when we had -4 F (-20 C). Many windmill palms (Trachycarpus fortunei)--including my own--have been planted in the Washington, DC area since 1994. Monday through Wednesday will be a major test for them and for many other plants that people have convinced themselves are perfectly hardy here! The coldest my own garden has seen since 2000 (when I purchased the property) is 6 degrees F (-14.4 C) in January 2004, and I think it may get colder than that on Monday night. I did cover my Schefflera delavayi because it's a long shot in my area, and also because I planted it rather late in the growing season. My other concern is Cycas panzhihuaensis, which has been in the ground for several years and has survived single digits on more than one occasion, but has been declining gradually since I transplanted it about 4 years ago.
Cycas panzhihuaensis in January 2013
Causes for concern are that (a) we we are forecast to have two very cold nights in a row, with the daytime high staying well below freezing during that period; and (b) this cold is coming early in the winter, so any damaged plants will have to wait several weeks before they can recover. Another cause for concern is that I have a cold microclimate within the city; while I do benefit from the urban heat island compared to locations outside the city, low temperatures in my garden are often several degrees lower than the official low at DCA (Washington National Airport) several miles away. The good news is that temperatures are supposed to be well above freezing both immediately before and immediately after this event, so the soil shouldn't freeze very deeply. That should make a big difference because when roots freeze, all bets are off!