No verb should have -ing in its lemma. However, nouns ending with -ing should keep the -ing in their lemma. Some words can be both nouns and verbs; categorize them based on the specific instance.

• writing_VVG beautifully has the lemma write
• beautiful writing_NN has the lemma writing

If a multi-word construction has been lexicalized into one word (i.e. rapidly-growing rather than rapidly growing, then it must be treated as a lexicalized adjective or noun rather than a verb. Most often, these become JJs, such as

• a rapidly-growing_JJ plant

Lexicalized nouns exist too, like

• the constant egg-laying_NN

The lemmas of these words keep the gerund, i.e. egg-laying and not *egg-lay.