Dianthus is a genus of flowering plants native to Europe and Asia. Most are perennial, although a few species are annual or biennial. All flowers in the genus dianthus have petals which are frilled with pink or consist of various shades of pink. It’s believed that the word “pink” may have been named after these flowers, and the correlation can be traced back as far as the 14th century.
Dianthus flowers are easy to grow in most climates, and are popular for use in flower beds and rock gardens. Most varieties will reach 18-24 inches (45-60 centimeters) in height with flowers 1-1 ½ inches (2.5-3.8 centimeters) in diameter. The flowers of dianthus are characterized by their ragged edges which are often darker in color than the remainder of the petal. Some popular varieties of the plant include dianthus caryophyllus or the common carnation, and dianthus barbatus also known as sweet William.
Prepare an area for planting dianthus with rich, well-drained soil and full sun. They will thrive in moderate climates, but if the weather becomes too extreme, they may die back or become diseased. Mildew can become a problem in areas of high humidity. Select an area of the garden with good circulation to prevent mildew and other diseases from afflicting the flowers.
Most commonly, dianthus flowers are grown from seed but can also be propagated from cuttings. If growing from seed, plant directly into the garden in mid-late spring once the ground has begun to warm and there is no longer a chance of frost. Plant the seeds approximately 10-12 inches (25-30 centimeters) apart, and cover lightly with rich soil. Seeds may also be started indoors six to eight weeks before the last frost.
If growing from cuttings, take them as soon as the first flowering is over, and trim off any lower leaves with sharp scissors or pruning shears. Dip the cutting into a hormone rooting powder, and place into a pot filled with a mixture of sand and perlite. Water thoroughly and place the pot in a sunny area with good circulation. Once the new roots are visible through the bottom of the pot, plant directly in the garden, spaced about 10-12 inches (25-30 centimeters) apart.
Once the seeds or cuttings are planted, water the area thoroughly and continue to water once or twice per week. If the area becomes very dry, water more frequently but do not over water. Make sure the soil is completely dry before watering again by placing your finger to the second knuckle into the soil. If no moisture is felt, water the area thoroughly.
Fertilize dianthus flowers with an all-purpose fertilizer once every month during the growing season to produce the best blooms. Cut the stems down to ground level once the flowers have died back in the fall. The plants will grow back the next year if they are perennial. Annuals will need to be replaced each year as necessary. If insects or disease become a problem, treat plants with an appropriate fungicide or insecticide at the first sign of infestation or infection.