Node-by-node boll mapping has been used to determine the effects of water, fertility, cultivar, and other parameters on cotton (Gossypium hirsutum L.) boll distribution. However, it is difficult to convert node-specific boll distribution into an overall estimate of boll accumulation. Vertical box and whisker analysis was used to incorporate vertical productivity on the plant, allowing simple indices based on the timing of boll production. This method was evaluated in a 2-yr research project at five locations in Georgia, Tennessee, and West Texas to determine the effect of environment on the relative maturity of individual cultivars. Six cultivars were chosen to represent varying maturities. The study was conducted on irrigated cotton in a randomized complete block design with four replicates at each location. The node at which 10, 25, 50, 75, and 90% of the crop was produced was determined for each cultivar at each location. The node of 50% production was highly correlated with the other percentiles and provided an overall estimate of the boll production range. Evaluating the node of 50% boll production yields a single parameter that can be used to define cultivar maturity. Environment also had an effect on maturity characteristics, however; some cultivars maintained mostly stable maturity characteristics over environment, but others were influenced by environment. It appears that, although the relative maturity of a cotton cultivar can be defined in a simple manner, the plant’s response to environment can alter the assigned maturity. Assigned maturities defined by vertical mapping would therefore need to be environment specific.