Last Updated on October 29, 2022 by Plant Mom Care
Dianthus caryophyllus, commonly called the carnation is indigenous to the Mediterranean. Its exact native range is unidentified as it has been extensively cultivated for over 2,000 years. Thousands of cultivars and hybrids have been developed for use in outdoor gardens or the flower industry.
This herbaceous perennial grows as high as 1 – 4 feet. The leaves are gray-green and around 6 inches long. The fragrant flowers are around 1 – 2 inches in diameter and come in bright pink-purple, white, red, yellow, green, and blue along with some striped variations.
There are two categories for these plants – border carnations with double flowers on 16-inch stems for gardens and florist’s carnations with double flowers on 3 – 4 feet stems mainly grown in greenhouses for the commercial florist trade.
Dianthus Caryophyllus Light Requirements
These plants prefer full sun for a minimum of 6 hours a day. Regardless of growing them as annuals or perennials outdoors or indoors, they require the sun to flower. Place them near a sunlit window indoors so they can get some bright sunshine. Although they will tolerate partial shade, they will produce fewer flowers.
Dianthus Caryophyllus Watering
They like regular watering but don’t like water-logged soil. Consistently watering them after the topsoil dries will provide the best results. Ensure the soil stays moist but not water-logged. Indoor potted plants should be watered every week.
Dianthus Caryophyllus Humidity
They grow better in low humidity however, an occasional misting during hot summers will help keep them cool.
Dianthus Caryophyllus Temperature
They prefer temperatures around 50 – 70°F and tolerate a low of 10°F. These plants can become dormant in temperatures above 85°F.
Dianthus Caryophyllus Soil
They prefer rich soil or soil with plenty of compost mixed in before planting, add 2 – 4 inches of organic compost mixed in the top of the garden beds. Reapply compost around the plants in spring before the new foliage appears.
Sandy soil with compost added in will provide good drainage and all the nutrients the plants need. They also prefer acidic soil rather than alkaline soil.
Potted plants require well-draining soil with equal parts of soil, compost, and perlite since they are prone to root rot if water-logged.
Dianthus Caryophyllus Repotting
Water the plant thoroughly the day before to avoid transplant shock when repotting. Prepare well-draining soil mixed with organic compost or granular fertilizer in the new pot.
Carefully remove your plant from the existing pot and plant it at the same level to prevent growth problems. Carefully fill the space around the plant with more soil and water thoroughly.
Dianthus Caryophyllus Propagation
These plants can be propagated by seeds, cuttings, or division.
Propagation from seeds
To cultivate seeds indoors, prepare a pot of well-draining soil mixed with compost eight weeks before spring begins. Then sprinkle the seeds on top and cover them with a light layer of soil. Enclose the pot in a plastic bag and move it to a warm place, keeping the soil moist. Once 2 – 3 leaves emerge, the plants can be moved into individual containers when they are around five inches tall.
Seed can also be directly sown outdoors in garden beds around 1/8 inch deep in spring. Keep the soil consistently moist and thin them out once they are five inches tall, keeping them 12 inches away from each other.
Propagation from cuttings
Take a 3-inch –long cutting from a healthy plant that finished flowering. Prepare a small pot filled with a mix of vermiculite and moist potting soil. Optional – dip the cutting’s end in rooting powder and insert it into the pot with one node just under the soil.
Move the pot to a sunny area and keep the soil moist. Once new foliage emerges in around a month, transplant it to the garden or a larger container.
Propagation by division
The division is best done after 3 – 5 years to rejuvenate the plant. This should be done in early spring as the plant is growing actively and not diverting energy toward flowering.
Avoid division in late autumn, as the plants won’t be able to grow new roots before they become dormant in winter. Water the plant thoroughly for a day or so before dividing it. Divide the plants in the morning as the roots are less likely to suffer damage as they will be hydrated.
Prepare the chosen location before time, so the divisions don’t remain out of the soil for long. Each division needs at least 1 square foot of space to grow.
The root system of these plants are tough and can deal with some abuse. Dig around 6 inches beneath the plant to grab most of the root ball. Cut into the stems and roots and divide them into new uniformly-sized plants, and plant the divisions in the prepared holes. Water at least once every week for the four weeks to get the plants established.
These plants are not heavy feeders. Potted plants can be fed with a balanced fertilizer every 6 weeks during their growing season. Outdoor plants will do well by adding organic compost into the soil every year to provide them with nutrients. You can use slow-releasing fertilizer in spring instead.
To increase repeat flowering, keep the plant tidy with proper pruning. Deadhead spent flowers, particularly on varieties that repeat bloom. This also helps prevent seed development while encouraging additional flowering.
Remove damaged or diseased foliage throughout the year. When autumn arrives, prune the plants down, leaving about two inches of stem sticking up over the soil for outdoor plants.
Dianthus Caryophyllus Common Problems
These plants can be vulnerable to diseases and pests. Fusarium wilt disease occurs when the Fusarium pathogen infects the plant, making its shoots slowly wilt and turn pale yellow.
The stems split apart as the infection spread, creating brown streaks in vascular tissue and root/stem rot. This is caused by prolonged exposure to high temperatures. It can’t be treated except by removing diseased foliage and keeping the plant under lower temperatures.
Rust and powdery mildew can also occur when there isn’t sufficient air circulation. Rust causes brown marks on the leaves. Remove infected leaves and treat the foliage with copper oxychloride.
Powdery mildew occurs on leaves due to high humidity and poor air circulation. Destroy infected foliage and treat the plant benomyl fungicide and increase air circulation by selective pruning to create ventilation.
These plants can also suffer from pests like aphids, spider mites, cabbage moths, cutworms, and sow bugs. Spray these pests off the plant with water and neem oil or insecticidal soap solution.
Fine webs on the plants with white or brown spotting are indications of spider mites. Mist the plants with a solution of neem oil to repel and kill the mites – repeat this after 2 weeks.
Aphids suck sap and damage plants. Spray the plants with a solution of neem oil to repel and kill these pests, repeating the treatment after 2 weeks to prevent further attacks.
Does Dianthus Caryophyllus return every year?
Plants growing in warmer areas continue growing through winter. They are classified as “tender perennials” and won’t survive prolonged low winter temperatures below 0°F. In these areas, treat the plants as annuals, with the hope that they will return in spring depending on the severity of winter temperatures.
Is Dianthus Caryophyllus an annual?
It should be treated as an annual when grown in cold climates.
What do you do with Dianthus in the winter?
Cut the plants down to 2 inches above the soil in autumn and protect them with a dense layer of mulch in winter.