Centaurea montana 'Amethyst Dream' has a deeper purple colour than is typical of the genus. It carries large blooms up to 5cm in diameter and its silver foliage tolerates heat and drought well. The plants have unusual, "shingled" flower buds, which create interest even before blooming in May. The variety is bred by Sahin in the Netherlands.
Dendranthema Igloo series has been improved by breeder Mark Smith at Yoder Brothers, based in the US. The varieties available in the UK are the coral red and yellow-flowered 'Rosy Igloo', the yellow double 'Sunny Igloo' and 'Warm Igloo', which has orange flowers with yellow centres.
Eryngium x zabellii 'Big Blue' is a bold garden plant, which bears 10cm-diameter electric-blue flowers and spiky foliage. This variety is recommended for mass plantings, as a novel container specimen or as a cut flower.
Penstemon 'Sweet Joanne' is a winter-hardy Penstemon. It features large, flared-trumpet flowers, which are lavender-pink outside but white with magenta veins inside. Foliage is narrow and glossy green.