Fostered by climate change the parasitic weed Phelipanche ramosa infests host crops such as tomato, hemp, tobacco and oilseed rape at an increasing rate. This weed can cause more than 80% yield loss of oilseed rape. To solve this issue knowledge on the way parasitic weeds infect oilseed rape is needed in order to design agroecological solutions. A report by Gibot-Leclerc et al. shows unexpectedly that the P. ramosa weed grows faster on slow-growing Brassicaceae – the oilseed rape family – than on fast-growing mouse-ear cress A. thaliana. This finding demonstrates for the first time that the growth of parasitic plants does not depend only of the growth speed of the host plant.