1 Salvia nemorosa 'Caradonna’ from the mildly aromatic silvery green leaves to the violet flower spikes with purple stems. Bees love the flowers that stay looking sharp long after the petals fall, thanks to papery bracts that hold their colour. Dead-heading – either little and often or in one go – encourages new flowering side-shoots till October. 'Caradonna’ loves sun; use it as a purple ribbon through late season grasses or, at 18in (45cm), it is the perfect centrepiece for a pot.
Rock Cress - Plant Aubrieta 'Cascade Blue' Excellent evergreen ground cover, producing cushions of pretty purple-blue flowers. It can be planted along the edge of a bed or lawn, or in the rockery, but is also very effective in a hanging basket displaying a profusion of colour.
Cerinthe major purpurascens "Blue Honeywort" - Outstanding selection with grey green foliage and beautiful blue blooms. Easy to grow in full to part sun, great for bees and butterflies. Annual, will reseed
Verbena bonariensis (aka the plant with these gorgeous purple blooms) is ok for bumblebees, but really comes into its own when it comes to butterflies and hummingbird hawkmoths. It self seeds well and you can take cuttings in the autumn so it's the plant that keeps on giving! #homesfornature