Gillyflower is another name for clove pinks, or Dianthus caryophyllus. During the Middle Ages, before the trading of spices from the Orient became commonplace in Europe, gillyflowers were steeped in wine to add their subtle clove scent and flavor. Gillyflowers are low-growing perennials whose flowers have single petals that bloom in late spring to early summer. They are hardy through USDA Zones 3 and 4, but benefit from some winter protection in the coldest areas.
Cut gillyflowers back in midsummer after they finish blooming. Cut the plants back by about half their height. This encourages them to produce more vegetative growth, which will increase the number of flowers the following year.
Mulch gillyflowers in late fall after the ground freezes. Apply a 2- to 4-inch layer of hay or straw. Do not use fallen leaves, as they can mat down and smother gillyflower.
Remove the mulch in very early spring, even before the snow is completely melted. Gillyflowers need good air circulation, especially at the base of the plants. Leaving the mulch on during unpredictable spring weather can cause them to rot during an early spring warm spell.