Vegetative and reproductive growth (fitness) of three Brassicaceae species was studied. Their fitness was highly affected by the length of growth and flowering periods. Thlaspi arvense is not suitable for cropping in semi-arid regions without irrigation. Camelina sativa is a good option as a rotational crop in these regions regardless of irrigation. Camelina microcarpa should improve emergence in order to stablish it as a viable crop.