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What is a Sweet William Plant?

Beautiful wildflower garden with double colored sweet william flowers in the forefront

Dianthus Barbatus

Dianthus barbatus is more commonly known under the name of sweet william. The sweet william is a flowering plant that is a member of the caryophyllaceae botanical family (the carnation plant family). In the well known Language of Flowers, this flowering plant symbolizes gallantry!

The genus name, dianthus, comes from a combination of two Greek words. The word dios, which translates to “divine”, and the word anthos, which translates to “flower”. The word barbatus is a latin phrase which literally means “beard of long weak hairs”, which is in relation to the glaucous leaves of the plant.

This dianthus plant is native to Europe and Asia but have been naturalized all over the world. They are a highly valued ornamental plant not only because it is beautiful, but because it has an exceptionally long blooming season, and they are very easy to care for.

Sweet williams make for a great companion plant or complimentary plant, but they certainly are not a show stopper. If you’re looking for something with a different growth pattern or a more extravagant blossom, we’ve compiled a list of Amazing Flowering Plants where you can browse for more garden options!

Tight flower cluster of light purple and white sweet william flowers against a blurred green background

Related: Sun-Loving Flowers | Water-Loving Flowers | Shade-Loving Flowers | Types of Flowers | Types of Flowers by Color | Types of Flowers by Alphabet | Types of Flower Colors

Beautiful garden display with three different colors of sweet william flowers in light pink dark pink and red

What do Sweet William Plants Look Like?

Flowers

Sweet william plants are cultivated for their lovely and dainty flowers. Sweet william flowers are borne as dense clusters that grow at the end of stiff and erect stems. They grow in clusters of up to 30 individual flowers, which is known as an umbel.

Each sweet william flower is 2-3cm in diameter and has 5 petals with serrated edges. These fringed petals will come in several different colors.

Flowers will usually bloom from late spring or early summer up until the first frost of the season. Their spicy clove scented nectar is very attractive smelling to various pollinators like bees, butterflies, and hummingbirds.

A wild sweet william flower will usually be red with a white base, whereas cultivars can range from having white petals, to pink, red, purple, or some cultivars come with variegated patterns! Other types will sometimes having a contrasting eye color.

Close up view of variegated sweet william flowers in white and purple in the sunlight

Leaves

Each aspect of the sweet william plant is ornamental, including its foliage! Leaves grow as prostrate rosettes closer to the ground.

Each sweet william leaf is lance shaped and usually around 4-10cm long and 1-3cm broad with a tapered end. Leaves are glaucous (covered in short fuzzy hairs) and they are greenish/blue color.

Growth Pattern

Sweet williams will grow as either a herbaceous biennial or as a short lived perennial plant, depending on its growing range.

Flowers grow in dense clusters at the ends of stiff and erect stems that grow from a prostrate rosette of lance shaped leaves. The stem will usually grow to heights between 12 and 24 inches.

Side view of beautiful clusters of sweet william flowers growing at the ends of long green stems with slender leaves

What are some Sweet William Varieties?

Dianthus Barbatus var. Barbatus

This variety of sweet william is the most common. It is native to southern Europe and is differentiated by its leaves. They can be up to 2cm more broad than other sweet william varieties.

Dianthus Barbatus var. Asiaticus Nakai

This variety of sweet william is less common than others. It is native to northeastern Asia and is also differentiated by its leaves. They are much more slender, and are up to 1cm less broad than other sweet william varieties.

Where is the Sweet William Plant Native to?

The sweet william is a native plant to both regions of southern Europe and regions of northeastern Asia. Since it is a rather resilient plant without any specific growth requirements, it has been naturalized in North America as well. These plants are wonderful with proliferation and extend their growing ranges through wildflower seed dispersal.

They grow wild throughout the mountainous regions of southern Europe; starting from the Pyrenees towards the Balkans. There are also disjunct populations throughout northeastern China and Korea that extend towards to southeastern most point of Russia.

Incredible wildflower field of sweet william flower clusters in red pink white and purple with dense forest in the background

How do you Propagate a Sweet William?

Starting Out

Sweet william plants can be propagated by several methods, including seed sowing, by collecting cuttings, or by the division of the root ball of an existing plant. Whichever method you decide on, the most important thing to know is the perfect conditions for germination.

If you’re looking to propagate through cuttings or division, ensure that you choose an exceptionally healthy looking cutting with un-wilted leaves and several flower buds. Planting the healthiest cutting will ensure the healthiest offspring.

This cutting can be kept in either a very organically rich pot of soil, or it can be kept in a large, clear cup of distilled spring water. This is a nifty way to propagate, as you can observe the cutting beginning to take root through the clear glass!

At this stage, soil should be kept moist and in a south facing window. The cutting should begin to start producing new roots in 3-4 weeks. If planted from sweet william seed, you’ll know that the seedlings are ready once they are almost an inch tall.

Transplanting

Now, it’s time to transplant your growing specimen to its outdoor home. Sometimes the most difficult step is deciding on the perfect spot for your plant!

Sweet williams prefer to exist in organically rich soil that is partially alkaline and is kept moist. They also prefer to live in full sunlight, with dappled shade in hotter climates for the afternoon.

Individual plants should be planted about 12 inches apart from one another, as they have wide spreading roots and crowns.

Lovely summer garden with three different colors of sweet william flowers growing in tall clusters above slender green leaves

What are the Growing Conditions of Sweet Williams?

Though the growing conditions of a sweet william aren’t particularly hard to achieve, they can be challenging to maintain even for the most seasoned gardener. Sometimes a sweet william will perish under unexpected climate conditions, but if they exist in perfect conditions, they can reseed every year and remain in your garden as a very long lived perennial.

Soil Type

Though the sweet william can tolerate many different soil types, it tends to thrive in loamy or sandy soils. The soil should also be partially alkaline.

The most important aspect that growing soil should have is its aeration. Soil should be well drained. Additionally, sweet williams thrive in organically rich soil. Accomplish this by simply incorporating compost into your existing mix.

Water Level

Sweet williams require a moderate amount of watering, and the natural precipitation of your area should suffice. If there happens to be a dry spell, repeat frequent waterings to ensure it doesn’t dry out too much.

Another way to keep soil moist is by adding a thick later of mulch on top of the top soil. This will not only protect delicate growing roots, but it helps keep moisture in the soil rather than it being evaporated.

Take care not to over water as they are not tolerant of water logged soils. They are however, tolerant of very dry soil as long as it is temporary.

Wild red sweet william flower clusters growing at the end of long green stems on the edge of a sandy beach

Sun Exposure

Sweet williams thrive in full sunlight conditions. If you happen to live in an area that receives particularly hot summers, perhaps choose a spot on your property that receives partial shade in the heat of the afternoon. This will help prevent leaf scorch.

Temperature

The sweet william plant is moderately cold hardy. Though it won’t survive colder winters, it may come back in areas that receive mild winters as a perennial species. It can exist in USDA zone 3 through 9.

Fertilizer

Sweet williams will respond very positively to fertilizer. During their growing season, apply a balanced liquid fertilizer every 6-8 weeks to help extend the blooming season and to encourage a second blossoms.

Pruning

Most gardeners recommend deadheading spent flowers to encourage a second bloom of flower buds. Otherwise, these plants tend to exhibit a naturally neat and manicured growth habit.

Intolerances

All in all, sweet williams are a wonderfully simple plant to care for once they are already established. Just remember that they are not tolerant to water logged soil or nutrient deficient soil.

Wild flower field in the sunlight with incredible bursts of flower clusters in pink and red of the sweet william plant

How are Sweet William Plants Used?

Ornamental Plant

The sweet william has become a very popular ornamental plant. It exhibits beautiful flowers that have a long bloom season, delicate and tapered foliage, and long and slender stems. Depending on the cultivar, flowers can come in a range of white, pink, red, purple, or variegated colors.

They are popular to use as container plants or facer plants, as well as a border plant specimen, and they make for great ground cover in rock gardens. Sweet williams are the perfect option for a country style cottage garden, or as an accent of color to a wildflower bouquet.

Edible Plant

Not many know this, but the sweet william flower is edible! It is often used as a beautiful and colorful garnish, or it can be steeped and used as a wildflower tea.

Wildlife Ecology

Sweet william plants are an excellent choice if you’re looking to naturalized your garden. Their spicy clove smelling nectar helps attract beneficial insects and pollinators like bees, butterflies, and hummingbirds.

Cultivated sweet william plants grown as border plants with a variety of flower colors growing in clusters of purple pink white and red

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