Rising feed costs and recurring feed shortages necessitate the investigation into alternative and underutilized feed resources. Nutritional characteristics of Juniperus species are either unknown or limited to leaves and ground material from small stems. Thus, the objective was to quantify nutritional characteristics, 48-h true IVDMD (tIVDMD), microbial gas production, and secondary compound characteristics of entire woody plant material of four Juniperus species: J. pinchotii, J. monosperma, J. ashei, J. virginiana, at immature and mature stages of growth. Immature plants had greater CP concentrations and lower NDF concentrations (P < 0.001) than mature plants regardless of species. Mature plants also had greater (P < 0.001) concentrations of ADF compared to immature plants with the exception of J.virginiana. In general, immature J. pinchotii, J. monosperma and J.ashei had greater (P < 0.02) tIVDMD, total 48-h and asymptotic gas production than mature plants. Immature J.monosperma and J.pinchotii  plants were more digested (tIVDMD: P < 0.001) than immature J.virginiana and J.ashei but tIVDMD did not differ in mature plant material across species. Condensed tannins (CT) were greater (P < 0.001) in immature J.pinchotii and J.ashei than mature plants; differences in CT concentrations among immature species were also detected (P < 0.04). Volatile oil yields were similar across maturity and species with one exception; immature J.pinchotii yielded greater (P < 0.02) volatile oil than mature material. Volatile oil composition across species varied and contained a range of 65 to 70 terpene compounds. The dominant terpenes across species were generally greater (P < 0.05) in immature vs. mature plant material with the exception of J.virginiana. Labdane acids were negligible in J.pinchotii, J.ashei, and J.virginiana, and greater in J.monosperma (P < 0.001). Ground material from mature juniper species, although inferior in nutritional quality compared to immature plants, is comparable to traditional low-quality roughage ingredients. Given that ground J.pinchotii has been successfully fed in lamb feedlot diets and nutritional similarities of J.monosperma and J.ashei to J. pinchotii 47 combine to suggest potential of J.monosperma and J.ashei as effective roughage ingredient alternatives.