The Perennial Plant Association selected Dianthus gratianopolitanus ‘Firewitch’ as their Plant of the Year 2006. This species of Cheddar Pinks, native to Cheddar Gorge, England, has spicy clove-scented flowers (the sweet fragrance of carnations) which face upward for maximum color impact. This German cultivar is one of the bluest-foliaged, one of the most tolerant of heat and varying soil conditions, and is one of the longest flowering of the many types of Dianthus.
This plant is similar to Dianthus ‘Bath’s Pink’ but the cultivar ‘Firewitch’ (‘Feuerhexe’) boasts single, shocking magenta-pink blossoms that are nearly fringed on the edges. They are attractive to butterflies and make excellent cut and dried flowers. The plants bloom heavily from late spring into early summer, sporadically throughout the summer, and often rebloom in early fall, particularly when deadheaded consistently.
The masses of flowers contrast beautifully with the silvery blue foliage. The tight mats of linear, needle-like, evergreen foliage grows about 4-6” tall (the flowers top out at 7-8” tall) and 18-24″ in diameter. This dianthus is not favored by deer once established. It is hardy in zones 3-8.
Being relatively short, ‘Firewitch’ is an excellent plant for the front of the flower border or as edging. It is an excellent plant for the rock garden or a raised bed where it can spill over the edges. Its spreading tendency makes it an outstanding groundcover, particularly on dry slopes. Many plants can be placed together to create a “pool” of deep blue foliage when not in bloom. Individual plants can be kept smaller by pruning the foliage in very early spring or after the first flush of bloom. This plant also works well in containers.
Dianthus grows best in loose, well-drained, neutral to slightly alkaline soils in full sun. It tolerates light shade, particularly in the afternoon. ‘Firewitch’ tolerates short dry periods, but needs regular watering during prolonged drought. Fewer flowers will be produced when grown in hot, dry areas. Don’t fertilize too much, as this promotes lush growth that may leaves the plants with gaps.
If grown in a container, plant in a mix with very good drainage and place in full sun or light shade. Water thoroughly when dry, but do not allow the medium to remain wet.
Dianthus can be propagated by division in early spring, just as the new growth begins to appear. This is recommended every few years because it tends to be a short-lived perennial otherwise.
– Susan Mahr, University of Wisconsin – Madison