The height growth and aerial biomass distribution (stems and leaves) of Medicago arborea and two varieties of Atriplex nummularia (one from Tunis and the other from South Africa) are shown below. Two irrigation treatments are compared with a control plot (only rainfall). For two years, plant height was measured every month. Twice a year, in spring and in summer, we collected three plants per treatment in order to quantify the biomass. Plants height and biomass accumulation are greater in irrigated plants than in unirrigated ones. Both species show great water use efficiency and may be used as forage shrubs in degraded areas. We consider that the variety of A. nummularia from South Africa is better than the variety from Tunis.