Dianthus Flowers: How to Grow, Care & Deadhead Dianthus Plants

Beautiful and fragrant, dianthus flowers are a hardy plant that can be grown all year round. They can be grown in pots or used as border plants.

If you’re looking for a versatile plant that’s easy to care for and pretty to look at, dianthus flowers should be at the top of your list! With so many varieties of dianthus available and the fact that they’re easy to grow and care for, there’s really no reason not to add these flowers to your garden!

What Are Dianthus Flowers?

Often referred to as “pinks” or “Sweet William”, dianthus flowers belong to the Caryophyllaceae family of plants, which also includes carnations. The genus Dianthus is a large one with over 300 species native to Europe and Asia. The flowers are prized for their spicy cinnamon fragrance with clove notes and they can grow to be between 15 and 46 centimetres tall. 

Dianthus flowers are usually pink, red, salmon, and white hues, while the foliage is thinly spread amongst the thick stems. These hardy plants can be grown all year round when properly cared for.

How to Grow Dianthus Flowers

You need to plant dianthus flowers in a location that receives at least 6 hours of sun a day. They thrive in partial shade or full sun and need soil that is alkaline and well-drained.

When to Plant Dianthus Flowers

Wait until the last frost of the winter has passed and the soil begins to warm up before planting dianthus. If you’re transferring them from pots, try to plant them at the same depth – between 30 and 46 centimetres in most cases. When watering them, water them at the base and avoid wetting the foliage as it can become a breeding ground for mildew.

Where to Plant Dianthus Flowers

Ideally, dianthus should be planted in full sun with soil that’s slightly alkaline and provides proper drainage. They’re prone to root and stem rot, so avoid overwatering the plant and don’t use mulch.

How to Plant Dianthus Flowers

Dianthus plants must be spaced at least 30 centimetres apart in alkaline soil. Seedlings and plants need to be planted at the same depth as the container they were grown in to ensure optimal growth.

If you are growing dianthus from seeds, you’ll need to start the process at least two months before the last frost. You’ll then be able to replant them in late autumn or early spring when the soil is warming up, although these hardy plants can survive all year round once established. Some plants are able to survive for up to two years given the correct growing conditions.

Spider mites can become problematic but insecticidal soap can help to get rid of them.

How to Care for Dianthus

They’re easy to care for and the instructions are straightforward. Ensure that the soil remains moist and add fertiliser to the soil every two months. A slow-release fertiliser will also be beneficial to ensure that your plant has the nutrients needed to sustain its growth.
Self-sowing varieties of dianthus plants exist, so to reduce the spread of the plant and ensure reblooming, deadheading is important.

How to Deadhead Dianthus

Once the petals have begun to wilt or fall off, you can deadhead the flower. You can also cut flowers to use as indoor décor for everything from weddings to birthday celebrations, which will serve the same purpose.

You can use scissors or pruning shears to cut back the dying flower stem, down to the last set of leaves before the base of the plant. The leaves are necessary for photosynthesis. You can add the offcuts of the flowers to your compost pile if you have one.

Keep an eye on your plant throughout the season and deadhead them whenever the need arises.

Do dianthus come back every year?

Yes, when grown in temperate climates that have well-draining soil, the dianthus will return each year. However, exposure to intense heat and cold will affect the plant’s ability to return.

Will dianthus bloom all summer?

Yes. In fact, dianthus will bloom throughout the year when properly looked after.

Do dianthus spread?

Yes, these plants have mat-like foliage that grows and spreads. Some variations of the plant are able to self-seed when not deadheaded in time. As a result, the plant will stop blooming and “focus” on self-seeding.

Do dianthus do well in pots?

Yes, dianthus will thrive in containers and pots, just be careful not to overwater them or let the soil dry out. It’s also important to ensure that the soil provides adequate drainage, and the container or pot has sufficient drainage holes.

Why are my dianthus dying?

The first thing to look out for is root rot, which is usually caused by excessive water or poor drainage. Dry soil as a result of too little water can kill the plant too, so it’s important to find the correct balance. Another thing to look out for is bacterial or fungal infestations. Aphids and spider mites can also affect your plants.

Is dianthus poisonous to dogs?

Yes, the dianthus is mildly toxic to dogs and can cause gastrointestinal issues. Repeat ingestion of these plants can cause more harm and will require immediate medical attention.

Are dianthus easy to grow from seed?

Yes, sow the seeds indoors around two months before the last frost. The seeds need to be planted 3 millimetres deep and then lightly covered with soil. Keep the soil moist and seedlings should emerge within 21 days. After this time, you can move them into the garden or keep them in the containers.

How many years do dianthus last?

These plants will return year after year. This growth can be encouraged by regular deadheading. The flowers on the plant, however, usually only last 8 weeks.

What do dianthus symbolise?

Dianthus flowers have been around for years and are considered to be the flower of the gods. They symbolise devotion, love, passion, and admiration.