This is a straightforward murder mystery with a large dose of romance and a good sprinkling of horticulture (sort of like 'Rosemary and Thyme' with sex). It's not ambitious, but it achieves its objectives with undeniable charm.
The plot is easy enough to follow, with some nice twists and turns right to the end, and the characters and their motives are believable. The cottage garden effects are laid on with a trowel (lots of heavy scents of honeysuckle and roses, birds chirruping and bees humming, you know the sort of thing), it's all rather nicely done and never feels over the top.. There are even a few gardening tips mixed in there.
All in all, a very enjoyable summer read. I would put it between 3 and 4 stars, but it left me in a pleasantly mellow mood, so I'll round it up to 4.