Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sambūcĕus, a, um, adj. [sambucus], of elder, elder-: arbor, Plin. 29, 4, 14, § 57 (Jahn, sabuceus): baculum, Aur. Vict. Vir. Ill. 10.