What links the word tarragon to words like dragon and drake?

Tarragon is a perennial herb of the wormwood species Artemisia dracunculus native to Europe and Asia. It’s also known as estragon, dragon’s wort or silky wormwood. Other names are available.

The word tarragon comes from Middle French targon (tarragon), from Medieval Latin tragonia (tarragon), from Arabic طَرْخُون‎ (ṭarḵūn – tarragon), from Ancient Greek δρακόντιον (drakóntion – dragonwort, Dracunculus vulgaris), from δράκων (drákōn – dragon, serpent) [source].

The word dragon comes ultimately from the same Ancient Greek roots, via Middle English dragoun (dragon, drake, wyrm), Old French dragon (dragon), and Latin dracō/dracōnem (dragon) [source].

The word drake (a mayfly used as fishing bait, dragon [poetic], fiery meteor), also comes from the same Ancient Greek roots, via Middle English drake (dragon, Satan), Old English draca (dragon, sea monster, huge serpent), Proto-West-Germanic *drakō (dragon), and Latin dracō (dragon) [source].

Incidentally, the word drake, as in a male duck, comes from Middle English drake (male duck, drake), from Old English *draca, an abbreviated form of *andraca (male duck, drake, lit. “duck-king”), from Proto-West Germanic *anadrekō (duck leader), from *anad (duck) and‎ *rekō (king, ruler, leader) [source].