A planting machine (1) for plants (2), such as seedlings (2), said plantingmachine (1)being provided for arranging plants (2) in a field (5) in such a way that,after being arranged inthe field (5), the plants (2) comprise an above-ground portion (3) thatextends above groundand an underground portion (4) that extends underground, said planting machine(1) comprisinga detection system for detecting the plants (2) after the plants (2) have beenarranged in thefield, said detection system comprising at least one measuring instrument (6)for detecting saidabove-ground portions (3) of the plants, and a method for mapping the positionof plants (2) ina field (5).