name of plant, lush
楙 centers on lush, vigorous growth, especially of plants. The 'name of plant' sense is a specific application of this idea of thriving vegetation.
楙 combines 木 (tree) with 矛 (halberd) and another 木, likely suggesting dense, weapon-like sharp growth or lush vegetation. The exact historical development is uncertain.
Two trees 木 with a halberd 矛 between them: imagine a halberd stuck in the ground, and lush plants growing thickly around it, so dense they hide the weapon.
For ボウ, picture a bow (ボウ) made from the lush, flexible wood of the two trees: bow -> ボウ, and the lush growth provides the perfect material.