Knowledge of the growth characteristics of guayule (Parthenium argentatum Grray) and the different co-products produced during plant development would be extremely useful for selecting guayule species with high rubber yields, productivity, and defining the best time for harvesting. In this work, the changes in biomass, rubber and resin characteristics of two Mexican accessions and a check variety with high rubber yields were monitored during a 3-year period, starting at the seeding stage. The plants were grown in an experimental dryland field and sampled almost every month for plant height, top spread, biomass, stem diameter, rubber and resin contents. The results show cycles of biomass accumulation which may be correlated with changes in rubber and resin content. The overall biomass increase was approximated using an exponential function of a growth constant and time. The constants obtained apparently depended on the accession.