The headword noun is normally neuter, not this masculine, and Adler reports that mss GM have the ste/rghqron also attested elsewhere, e.g. Hesychius sigma1759.
As to its meaning, LSJ registers two related ones: 'love-charm, applied to various plants', and (with examples in tragedy) 'love itself'. Given the Suda's glossing, the second of these must be intended here; for the first see Hesychius loc.cit.