ichidan verb, intransitive verb
become frayed and disheveled; become fluffy
Describes hair, grass, or similar things becoming tangled, frayed, or fluffy in a wild, unkempt way. Often used for hair that is messy or grass that is overgrown. The cross-reference to ほうける (sense 3) suggests a related meaning of being absorbed or lost in something, but here the primary sense is physical dishevelment.
See also: ほうける
風で髪が蓬けてしまった。
My hair got all disheveled from the wind.
庭
The grass in the garden has become overgrown and unsightly.