Gathering indication of flowering, including Northern heather (8)

'gathering' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe there's a link between them I don't understand?

'indication of flowering including northern heather' is the wordplay.
'indication of flowering' becomes 'bud' (I am not sure about this - if you are sure you should believe this answer much more).
'including' means one lot of letters goes inside another.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'heather' becomes 'ling' (synonyms).
'bud' enclosing 'n' is 'bund'.
'bund'+'ling'='BUNDLING'

Can you help me to learn more?