Yesterday’s post, ASDM: Agaves in the snow, prompted me to do a little bit of research into the cold tolerance of agaves. There’s a wealth of information available online and in books, but much of it is in bits and pieces. I attempted to compile a list that is as complete—and hence as useful—as possible. The tab “Sources” in the spreadsheet below lists the sources I relied on most; where they disagreed with regard to the cold hardiness of a given species or cultivar, I picked the mean value and rounded it up.
Agave ovatifolia, the whale’s tongue agave, is one of the best choices for cold and wet winters
My hope is that this list will be a useful reference for your own trials. Please bear in mind that cold hardiness depends on more than just temperature. For the majority of agave species, the most crucial factor aside from the absolute air temperature is how wet or dry the soil is when a cold spell hits. Completely dry soil allows agaves to withstand colder temperatures than they would be able to tolerate if the soil is wet. The worst-case scenario would be a deep freeze following rain, especially if the soil is heavy and has poor drainage.
You can give your agaves the best chance at winter survival if you plant them in loose, well-draining soil. Many gardeners aren’t blessed with such conditions so don’t be frustrated. Agaves have a shallow root system so you only need to amend the soil to a depth of 8-12 inches. Adding coarse inorganic material such as pumice, decomposed granite, chicken grit, or even small rocks or pebbles is a great way to improve your soil. Better yet is to plant agaves (and other succulents) on a slight mound so the rain runs off more quickly; that’s the approach I prefer.
Agave montana, another good choice for wet-winter climates
Finally, some agaves are able to handle cold, wet winters better than others. Agave montana, Agave ovatifolia, and Agave parryi ‘JC Raulston’ have proven themselves under these conditions.
I would love to know what your own experience is. Which species work well in your climate? Please leave a comment below.
P.S. I’ve added the table below to a page called “Agave Cold Tolerance.” You can access it at any time from the menu bar at the very of top of the page.