Refers to the new buds or shoots appearing on plants in spring, or the process of buds opening. Often used poetically or in nature writing.
See also: 芽吹く (めぶく)
In spring, you can see budding on the trees in the garden.
I can't wait for the budding season.
Noun form of the verb 芽吹く (めぶく), from 芽 (め, 'bud') + 吹く (ふく, 'to blow' or 'to sprout'). The exact historical derivation is uncertain, but it describes the emergence of buds as if blown forth.