Sweet williams: flowering, varieties & toxicity

This beautiful perennial with cottage garden flair displays spectacular flower colours. Although sweet williams usually only flower in their second year, it is worth waiting for their pretty flowers.

Sweet williams (Dianthus barbatus) come in different sizes and colours. We have put together a selection of the most beautiful varieties and reveal when you can look forward to the beautiful flowers. We explain everything about the topic planting sweet william in our special article.

Sweet williams: Characteristics and origin

Sweet williams belong to the carnation family (Caryophyllaceae) and originate from southern Europe and parts of Asia. Dianthus barbatus is usually a biennial perennial – in the first year of growth only a rosette of leaves is formed, from which in the second year, after a successful overwintering of the sweet william, the flower stalk grows up together with the flowerheads. These are characterised by many fringed and tufted upper leaves, also called bracts, which remain in this form after flowering. In total, the sweet william reaches a height of between 40 and 60 cm. The bearded appearance of the flowerheads is the reason for its German name: the bearded carnation. The flowers not only look pretty, but at the same time exude the typical, distinctive carnation scent – like many relatives within the plant family. The colour of the individual flowers is very varied depending on the variety and can be red, white, pink or scarlet, patterned or monochrome. The lanceolate leaves of the sweet william are lush green and arranged crosswise. The beautiful sweet william is used in flower beds, especially in cottage gardens and borders. The carnation plant can also be kept in the vase as a beautiful cut flower for 10 to 14 days.

When do sweet williams flower?

Sweet william have their main flowering period from May to June, with some varieties flowering later, into August.

Are sweet williams bee-friendly?

Yes, the supply of nectar and pollen is relatively low, but the sweet william is nevertheless readily visited by a wide variety of visitors such as bees, birds and butterflies. Varieties with double flowers, on the other hand, are of no interest for insects.

The most beautiful varieties

The best-known varieties of sweet william only flower in their second year, but there are now also annual varieties that delight with new colours and flower shapes. Therefore, we have put together a handy selection of the most beautiful and recommended varieties of sweet william.

• ‘Amazon Neon Cherry’ is an example of an annual sweet william variety. It grows up to 40 cm high and flowers from June to August, depending on when it is sown. As the cultivar name suggests, it exhibits flowers in a strong cherry red. The variety is particularly attractive because of its resistance to rust infestation and its long shelf life as a cut flower of approx. 12 days.
• ‘Bodestolz’ features a fascinating mixture of dark red to light pink, partly patterned flowerheads. The variety is also cultivated as an annual and flowers from June to September, provided that the seeds are pre-picked from February onwards. In total, you can look forward to sweet williams up to 50 cm high. The risk of rust infestation is also low with this variety.
• ‘Sweet White’ also flowers in the year of sowing from June to August and delights with radiant, white flowerheads that reach a height of up to 60 cm. As a cut flower, the variety keeps between 10 and 12 days in a vase. Unfortunately, the variant is somewhat more susceptible to rust infestation and should therefore be checked more frequently for symptoms.
• ‘Sooty’, also traded under the cultivar name ‘Nigrescens’, is a biennial sweet william cultivar. Impressive here are the deep black-red flowers that appear in the second year from June to August. It is considered an extremely robust variety and grows to a height of approx. 35 cm.

• ‘Scarlet Queen’ is a very flowering biennial sweet william variety. It lasts up to 14 days in the vase and delights with scarlet flowers, which it displays from May to June. Overall, this variety grows to a height of approx. 45 cm and is recommended by experts as an outdoor cut flower.
• ‘Oeschberg’ also belongs to the biennial and robust sweet william varieties. It keeps fresh in your flower vase for up to 13 days. The foliage of this variety is dark green, the flowers show a beautiful, strong purple from June to July.With a height of 50 cm, ‘Oeschberg’ belongs to the tall-growing varieties.

• ‘Messenger Mix’ exhibits different flowerheads. White to scarlet, patterned and plain – there’s something for everyone. They grow up to 60 cm tall and are in full bloom from May to June in the second year. The extraordinary thing about this variety is its long vase life: you can enjoy the cut flowers for up to 14 days.
• ‘Green Trick’ is not a bee-friendly variety, but it is an interesting eye-catcher. Also known as grass carnation, it is mainly used in floristry and features iimpressive green flower balls. Instead of petals, only bracts are formed. This flower is therefore not usable for insects. As far as rust is concerned, the risk is very low with this variety and it can be enjoyed as a cut flower for up to 3 weeks.

Are sweet williams poisonous?

No, sweet williams are neither poisonous for us humans nor for dogs or cats. The flowers are even edible and can be used as decoration, for example for salad. The taste is spicy and slightly sweet. However, sweet williams that you have bought pre-cultivated from a specialist shop should be consumed with caution: They may have been treated with pesticides.

The pretty cow herb (Vaccaria hispanica) also belongs to the carnation family and enchants with its delicate flowers. Read here how to plant and properly care for the beautiful perennial.