Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. plantārĭum, ii, n. [planta], a nurserygarden, nursery: plantaria instituunt anniculasque transferunt, et iterum bimas, Plin. 13, 4, 8, § 37: caedua, id. 17, 20, 34, § 149.
2. plantārĭum, ii, n. [planta], the sole of the foot: quod tamen de plantario ferri orietur (statua), Vulg. Dan. 2, 41.