Dianthus plants produce long-lasting pink flowers and are generally easy to care for. They do best, however, in moderate climates, as too much cold will kill them, while too much heat will cause them to go dormant.
Read more about their varieties, and how to grow for it here.
Dianthus Quick Facts
|Origin||Asia and Europe|
|Type||Flowering perennial, annual, or biennial|
|Watering||Maintain moist soil|
|Light||Full sun to partial shade|
|Height||Up to 3 feet|
|Toxic||Toxic to dogs, cats, and horses|
There are over 300 varieties of dianthus, encompassing perennials, annuals, and biennials. They grow to various heights, with some having a low growing nature that is suitable for use as ground spread, while others have a mounding habit.
Chinese Pink (Dianthus chinensis)
This perennial dianthus plant is hugely popular. It is heavily adorned with flowers that are often bicolor with a dark center. It can grow to heights of anywhere from a petite 6 inches up to 30 inches. It enjoys full sun but thrives in cooler temperatures, and in hot climates will need some shaded protection from afternoon sun.
Sweet William (Dianthus barbatus)
This short-lived perennial or biennial is native to southern Europe. Its flowers bloom in clusters on erect stems which can measure up to 24 inches tall, lasting from around May to October.
Cheddar Pink (Dianthus gratianopolitanus)
This evergreen perennial has seen a wave of popularity since receiving the Award of Garden Merit from the Royal Horticultural Society. The small flowers are heavily scented and are attractive to butterflies and hummingbirds, but the plant is resistant to deer. The foliage of this variety is grass-like, and work well as ground cover, border edging, and in flower beds or containers.
Dianthus Care Instructions
Dianthus plants like to be grown in moist soil, but they can fall victim to root rot and stem rot, so it’s imperative that they be planted in well-draining soil. If they had the choice, they would prefer to be in an alkaline soil. Test the pH of your soil and try to correct it if it is on the more acidic end of the scale. Neutral to alkaline will work well, but acidic soil may cause the plant to struggle.
Water the plants according to how much moisture remains in the soil. You can allow the soil to almost dry out before watering it again, ensuring when you do water it that you do so thoroughly. Never let the soil completely dry out, as this thirsty plant needs moisture in order to continue producing plentiful flowers.
Like many flowering plants, the dianthus loves the sun. Ensure you position it in a spot that gets at least six hours of full sun a day, to enable it to produce the blooms it is famed for. It can tolerate some shade, but too much shade will cause it to struggle with flower production, and the plant can become leggy in an attempt to reach towards the light. If full sun is not possible, choose a position that offers a few hours of shade in the afternoon. This will ensure the plant gets plenty of morning sun, and will also protect it from becoming too hot in the strong afternoon heat.
One of the reasons this plant has remained so popular for such a long time is its ability to withstand a wide range of temperatures. It can be grown in most climates that do not experience extreme temperatures. Unlike many flowering plants, the dianthus will even withstand light frosts, but temperatures below 40° F cannot be tolerated, and deep freezes will see the plant die down to the ground. Hot temperatures can also cause problems for this plant, and highs of 85° F and over should be avoided. Very hot temperatures such as this can cause the plant to enter a period of dormancy to protect itself.
Dianthus plants do not like high humidity and grow well in average air conditions.
Dianthus plants are easy to propagate from stem cuttings, and this is an inexpensive way to replace older plants that are coming to the end of their lifespan. Propagation works best in spring or summer when plant cells are dividing quickly, so rooting happens more easily. Take several cuttings from healthy fresh stems that have not yet flowered.
You will need a length of stem with around five sets of leaves on it, cutting it from the main plant just below a node where a set of leaves join the stem. Remove all of the lower sets of leaves from your stems, and prepare a container of moist potting soil to root the stems in. Ensure the potting soil is moist, and make several holes in the soil with a pencil. Dip the raw end of the stems in rooting hormone, and then insert them into the premade holes.
They should be spaced apart enough so that the leaves are not touching, and inserted deep enough so that only half of the stem is left poking out from the soil. Cover the stems and container with a plastic bag to create a humid environment and set it in a bright spot away from direct sunlight, such as a windowsill. Maintain moist soil and wait for the stems to root. Once new growth occurs on the visible parts of the stem, this is an indication that roots present and getting stronger, and they can be transplanted to a more permanent home in a larger container or directly into the ground (Gardeners World Magazine).
Pruning your dianthus will help to encourage more bushy growth and flower production, and the plant is able to tolerate severe trimming, so you can prune it enthusiastically without worrying about causing damage. Remove spent flowers as they wilt, and trim any dead or damaged stems throughout the year. You can perform two full prunings each year, one after the first set of blooms have faded in early summer, and another in the fall when annual dianthus plants begin to die back naturally.
When the first set of blooms have completed, you can trim the plant back to around half its size. The plant will quickly recover with summer growth, and the pruning will encourage more bloom production and a fuller, bushier shape. As your annual dianthus begins to die back in the fall, you should prune the whole plant back to almost ground level, leaving just a few inches of stems. This will help to preserve the plant's energy until the following spring when it begins to actively grow again.
Dianthus plants typically flower from early spring right through to fall. The flowers are available in a range of colors, including pink, red, white, and purple, though most varieties feature some shade of pink, which is how they became commonly known as ‘pinks.’ The flowers each have five petals and typically have serrated edges. They are enormously popular in home gardens because the flowers are so easy to grow and care for and offer a bright and cheerful aesthetic. These flowers also make excellent cut flowers and are renowned for their long-lasting quality.
Common Pests and Diseases
Newer varieties of dianthus have been bred to be disease and pest resistant. They are mostly problem-free but can sometimes play host to carnation flies, which lay eggs in the foliage of the plant. These can be kept under control with the use of garlic, either as a companion planter or by spraying the plants with garlic tea.
If you have any questions or further advice regarding dianthus plants, please leave a comment below. And don’t forget to share this page with other flower growers!