The Collaborative International Dictionary
Mossing
Moss \Moss\, v. t. [imp. & p. p. Mossed; p. pr. & vb. n. Mossing.] To cover or overgrow with moss.
An oak whose boughs were mossed with age.
--Shak.
Wiktionary
mossing
vb. (present participle of moss English)