edible amaranth, straw basket
蕢 centers on two distinct concrete objects: an edible amaranth plant and a straw basket. These meanings do not share an obvious conceptual link, so treat them as separate senses.
蕢 combines the plant radical 艹 with 貴, which likely contributes sound. The exact historical development is uncertain, but the structure suggests a plant name or a basket made from plant material.
The grass radical 艹 sits above 貴, like valuable plants growing in a field. Picture an edible amaranth plant, or imagine weaving those valuable grasses into a straw basket.
For カイ, imagine a straw basket full of amaranth being carried by a kite: kite -> カイ, and the basket sways in the wind.