Hardiness Ratings
   Although there are a number of web sites and resource books that offer bamboo hardiness data to the gardener, the information can be confusing and is sometimes conflicting. Some sources list temperatures at which leaf damage will begin to occur while others list temperatures at which culm death will happen. These temperature estimates also generally assume that the bamboo is exposed to the listed temperature for only a matter of hours, as opposed to a lengthy exposure to extreme temperatures. There are many variables that affect bamboos response to winter conditions including extreme temperatures, cold dry winds, prolonged periods of below freezing temperatures, and the 'suddenness' of the cold snap. I have seen bamboo that is generally considered to be hardy to subzero temperatures, exhibit serious leaf damage when temperatures suddenly drop to subfreezing after a period of late fall warmth. How is the gardener supposed to feel when a bamboo listed as hardy to -15F suddenly shows serious leaf damage at +23F?

   For these reasons, I have decided to avoid using specific temperature ratings in terms of bamboo hardiness. Instead, I am using a report card style rating system. The different grades presented here specifically relate to bamboo grown in the southern portions of Indiana, Illinois, Missouri, Ohio, Pennsylvania, and the northern part of Kentucky. I grouped these areas together because not only are our winters similar, we also share similar annual precipitation amounts, summer temperatures, and length of growing season. Other areas of the US listed as USDA zone 6 should expect similar results but local climactic factors may result in somewhat different performance. In USDA zone 5 one should lower each of the following ratings by at least one full grade, while zone 4 gardeners should only consider growing those species with A & B ratings and should expect them to perform as C & D grade bamboos. Areas colder than zone 4 are unlikely to have much success growing bamboo.

  The ratings below are for the species that I currently have in-ground and represent the degree of cold damage one can expect in an average zone 6 winter. As my plantings mature I anticipate that some species may exhibit increased hardiness and their rating will be upgraded. For winters which are colder than an average year, the performance will be approximately 1 grade lower while winters milder than normal may result in a 1 grade higher rating. It is also assumed that the bamboo is well-established (at least 4 years in-ground) and healthy going into winter. Until well-established, bamboo will not exhibit its eventual hardiness and will be more severely impacted by winter conditions.

  As I continue to develop this web site, I will create pages containing specific information about each species. If the species name is in italics and underlined, you may click that link for more information and photos of that species.