Tarbush (Flourensia cernua  DC) is a rapidly increasing Chihuahuan Desert shrub. Use of livestock to control tarbush is being examined. Whole plants (n=120) were harvested to assess nutrient composition during 3 years across 4 growth stages: early (EG), midpoint (MG), late (LG) and senescent (SG) growth. Plants were air-dried then leaves were removed and freeze-dried. Nitrogen concentration was greatest for EG, lowest for SG, and no different between MG and LG (P <.05; 3.95, 2.82, 2.77 and 2.62% of DM for EG, MG, LG, and SG, respectively. Soluble N content was greater and ADIN content was lower for EG (P<.05) than other stages. Insoluble N declined with advancing maturity (P<.05). As a fraction of total N, insoluble N decreased and soluble N increased with maturity (P <.05). IVDMD and was greater for EG than the other stages (P <.05; 66.8, 61.0, 60.5 and 60.4% of DM for EG, MG, LG and SG, respectively. Calcium concentration increased and P content decreased with maturity (P <.05). Concentrations of NDF and ADF were lowest for EG (P <.05) but did not differ among later growth stages. ADL content was least for EG and less for MG than LG or SG (P <.05). Condensed tannin content tended (P <.10) to increase with advancing season. Total phenolics concentration was least for EG (P <.05)and not different among the other growth stages (6.6, 8.1, 7.9 and 7.6% of DM for EG, MG, LG and SG, respectively). Nutrients and antiquality variables exhibited patterns normally associated with advancing phenology. Across seasons and years, tarbush was of reasonably high quality (3.0 % N, 62.2 % IVDMD, 20.8 % NDF, 17.0 % ADF, 1.51 % Ca and 0.15 %  P, DM basis) and low in antiquality factors (0.1 % ADIN, 6.6 % ADL and .34 % condensed tannins, DM basis), with the exception of total phenolics (7.6 % of DM) and ether extract (13.6 % of DM).