A Lady of True Distinction by Grace Burrowes

Hawthorne Dorning either finds a way to turn his family’s vast botanical resources into a successful commercial venture, or the estate the Dornings have called home for centuries could be broken up. He loves the land and he’s never shied away from hard work, but he knows nothing about creating perfumes or fragrances.
Margaret Summerfield has put aside her passion for scent-making to tend to the serious business of raising her little nieces. She’s no longer the girl who wandered the countryside by the hour, lost in the pleasures of nature, nor does she want to be. Hawthorne needs her help, but what does he have that could possibly tempt to Margaret to entangle herself with his dreams?