Agricultural Research Division of IANR


Date of this Version



Frontiers in Ecology and the Environment 13:8 (Oct 2015), pp. 450-451. doi: 10.1890/1540-9295-13.8.450.


Copyright 2015 The Ecological Society of America. Used by permission.


In 2012, much of the US Midwest was gripped in one of the most severe droughts on record. While conducting experimental fieldwork at a site in Nebraska during June of that year, I noticed a single musk thistle (Carduus nutans; Figure 1) that appeared to be in the bolt or early flowering stage, which is typical for the species at that time. Here, however, two things were unusual: this plant was less than 1 meter tall (with adequate moisture and light, musk thistle typically grows to heights of 1–2.5 meters before flowering), and was only 3 months old (the bolt stage, when it would produce a flowering stem and set seed, typically occurs during the thistle’s second year). Interestingly, this plant died less than 3 weeks later, without producing flowers or seeds. Apparently, this plant was unable to successfully spearhead an invasion in this field because it could not complete its normal life cycle during a period of drought.