Larger plants tend to be more branched than smaller plants in some species. The nutrient diversion hypothesis for apical dominance proposes that the apical meristem of a plant acts as a strong metabolic sink, depriving nutrients from latent axillary meristems and thereby promoting strong directional (e.g., vertical) growth with little branching. Hence, larger plants may be more branched because they may have more resources that cannot all be sequestered by the apical meristem, leaving an excess available for branch production from axillary meristems. However, larger plants may also be more branched because they incur greater damage from herbivores that disrupt apical dominance. Hence, the availability of nutrients may be a confounding factor for studies of response to herbivory through effects on apical dominance. In order to distinguish these effects, we applied nutrient and water supplementation to two natural populations of Verbascum thapsus in which herbivores were excluded to test the hypothesis that nutrition level, including water, plays a role in determining the extent of branching. We used a full factorial experimental design involving three levels of resources (control, water, and water with fertilizer) and shoot apex removal. Both a single-season experiment and a two-season experiment were performed, the latter involving only the three levels of resources as treatments. Branching was increased by shoot apex removal and was enhanced by the addition of nutrients but only in clipped plants. Thus, the nutrient diversion theory does not solely explain the strong apical dominance exhibited by V. thapsus; an alternative hypothesis involving weevil herbivory is indicated that may further explain the growth form and branching patterns in this species.