Book 1 is Blue Dahlia, about Stella and Logan. A widow, with small children and a landscape designer, who clash.
Book 2 is Black Rose, about Rosalind and Mitchell. The owner of the garden centre and the academic, she hires to 'do the family tree'.
Book 3 is Red Lily, about Hayley and Harper. A single mum and Rosalind's son, distant relations, in that convoluted Southern USA way.
Set in Memphis, Tennessee, in the garden centre, called, In The Garden.
Gardens, ghosts and genealogy describes the trilogy brilliantly. Toss in romance, family and gossip and you won't be able to put them down.
Do start with book 1 or you won't get the full story.