When Should You Use a Comma for the “Not Only,” “But/but Also” Construction?

When should you use a comma for the “not only,” “but/but also” construction?

When “not only” and “but” each precede an independent clause, use a comma before “but.”

• Not only do sunflowers add striking colors to a garden, but they also provide sustenance for pollinators.

When “not only” or “but” precede a phrase or a word, omit the comma before “but.”

• Not only do sunflowers add striking colors to a garden but also sustenance for pollinators.
• I want not only to grow sunflowers but also tomatoes.