Seeds of Dianthus barbatus atrosanguineus Sweet Williams, Poets Pink or Sweet John. This dianthus is the deepest of all the deep reds with attractive green foliage and large clusters of single blood red flowers. They flower all summer from May to August, and they are intensely fragrant with a delicious rich perfume. Grows equally well in sandy to clay soils. Growing 12-18″ tall and 8-12″ wide. Hardy to zones 2-9 in full sun.