overgrown with grass, weedy
茀 centers on vegetation that has grown thick and tangled, making a place weedy or overgrown with grass.
茀 combines the grass radical 艹 with 弗, which likely contributes a phonetic element. The exact historical development is uncertain, but the structure suggests a plant-related meaning.
The grass radical 艹 sits above 弗, like a tangled mass of weeds that has completely covered the lower shape. Picture a neglected field where the grass is so thick it hides everything underneath.
For フツ, imagine a foot stepping into the overgrown weeds and getting tangled: foot -> フツ, and the thick grass makes it hard to move.