Here’s a short report and a few pics of how our clumping bamboos performed during last week’s record cold snap.
It’s raining and temperatures are back in 40’s this week but last week, the night temperatures in much of southwestern WA dropped below 10 degrees F., with daytime highs in the teens and twenties. Here at the nursery, we saw temperatures drop to 7 degrees F. a couple of nights, and to about 12 degrees a couple more nights (however, with hardly a breath of wind during the coldest days). These temperatures are the coldest I have seen here in the last 10 years, so it’s a good time to assess the cold performance of our popular clumping bamboos.
My most popular Fargesia species didn’t even blink at the cold, that includes container and field plants alike. Most of the containers are in an unheated hoop house, but even the ones outside fared very well. Below is Fargesia robusta, picture taken after the coldest weather passed, but still frosty.
Fargesia ‘Rufa’ also fared very well. Below is one of the many ‘Rufa’ planted out here at the nursery. All of them came through unscathed.
My favorite of the clumpers is Fargesia scabrida. Containers and plants in the ground survived without any damage. Pictured below, is a plant I pruned for a demonstration video How to Prune a Clumping Bamboo . If you compare the video images to the pics below, you can see how the canes have darkened with exposure to sun and cold temperatures.
Fargesia denudata had mixed performance. Plants in the ground came through looking fantastic, as did most of the container plants. Some containers, however, suffered some pretty severe leaf keel, even in the protection of the hoop house (pictured below).
I have one Thamnocalamus crassinodus planted out. Last winter it died back to the ground, but the new growth that came up in spring 2009 survived this cold snap, although I am not going to get my hopes up until the worst of winter is over (about February). Below, plants in the hoop house suffered severe leaf keel, but may partially recover.
Yushania ‘Pitt White’ is another marginally hardy plant for our area. It will regularly die back to the ground in our colder winters, but is vigorous enough that it will come back and increase in spread over the following growing season. Below, a container of ‘Pitt White’ that was left outside, unprotected. This one is fried bad enough that I will have to cut the stems back to the top of the container. Plants in the protection of the hoop house showed no permanent damage.
Bambusa multiplex ‘Alphonse Karr’ is a clumping bamboo that continues to surprise and impress me. At home in the heat of southern Florida, the plants in our hoop house not only survived the cold snap, but persevered with very little leaf damage (pictured below). I promote this bamboo as a house plant for our region (one of the few bamboos that will thrive indoors) and it amazes me that a sub-tropical bamboo will survive with a frozen rootball in an unheated hoop house!