A new and distinct Senecio plant named ‘AMICU1908’ which is characterized by a compact and upright growth habit, a glaucous greyed-green stem, glaucous greyed-green foliage, narrowly oblanceolate and falcate foliage, semi-terete to terete foliage with an obvious longitudinal channel running the length of the leaf, foliar margins that occasionally develop two spines on opposite sides of the leaf, and the stability of these characteristics from generation to generation.