Murder in the Secret Garden by Ellery Adams

Murder in the Secret Garden by Ellery Adams is part of the Book Retreat Mystery series - I always find her book covers intriguing. Jane and her twin boys live in the hunting lodge of Storyton Hall, both buildings were moved from England in the 1830s to western Virginia. This, apparently, is not uncommon and several buildings (and bridge) have been moved from other parts of the world to the U.S. Agecroft Hall, a Lancashire Tudor House, was moved to Virginia in the 1920s.

From the cover:
There is a hidden garden bordering the grounds of Jane Steward's book-themed resort - a garden filled with beautiful but deadly plans such as madrake and nightshade. Tucked away behind ivy-covered walls and accessible only through a single locked door, as described in the pages of Frances Hodgson Burnett's classic novel, the garden is of special interest to Jane's current group of guests, The Medieval Herbalist. But when one of them turns up dead, Jane must discover whether a member of the group has come to Storyton Hall to celebrate their passion for plant lore or to implement a particularly cruel means for murder.