Well up in colour (7)

I believe the answer is:

suffuse

I'm a little stuck... Click here to teach me more about this clue!

'well up in colour' is the definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Maybe they are linked in a way I don't understand?

This is all the clue.

Can you help me to learn more?

(Other definitions for suffuse that I've seen before include "Of colour, spread slowly throughout" , "Spread; permeate" , "Flood through" .)

I've seen this clue in The Telegraph, The Guardian and The Globe and Mail.

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