Dragonhead (Dracocephalum moldavica L.) is a hardy annual plant with aromatic, balm scented green foliage, belonging to the Lamiaceae family. The essential oil content and its composition in this species exhibit considerable variation depending on the plant’s origin. An experiment was conducted to investigate the response of dragonhead to various plant densities (10, 15, 20, and 30 cm), using a randomized complete block design. Essential oil content and several biochemical traits were measured. The treatment-by-trait biplot of the mean performance of dragonhead treatments explained 90% of the total variation in the standardized data. Traits such as dry yield performance, flavonoid 270 nm, and total flavonoids were positively associated, while essential oil content, flavonoid 330 nm, and height of the first flowering branch, along with anthocyanins and flavonoid 300 nm, also showed positive correlations. Additionally, the number of secondary branches and stem diameter were closely associated. Conversely, essential oil content was negatively correlated with anthocyanins and flavonoid 300 nm. Among the treatments, 15 and 20 cm plant spacing produced the highest essential oil contents, with 20 cm showing less variability than 15 cm. Narrower (10 cm) or wider (30 cm) spacing did not contribute positively to essential oil yield, indicating that medium spacing, particularly 20 cm, is optimal for dragonhead cultivation.
