jujube
棗 refers specifically to the jujube tree or its fruit, a type of date-like fruit. The meaning is narrow and concrete, without abstract extensions.
棗 is a pictograph of a thorny jujube tree, with the doubled 朿 (thorn) components representing the tree's spiny branches. The modern form retains this doubled-thorn structure.
Two thorny 朿 components stacked together: imagine a jujube tree covered in small thorns, with the fruit hanging among the spines.
For ソウ, picture a jujube tree growing in the soul of a garden: soul -> ソウ, and the tree's thorny branches reach upward.