How to Grow and Care for Sweet Williams

Sweet Williams plant with bright and light pink frilly flowers

The Spruce / Gyscha Rendy

The sweet William is a short-lived, herbaceous perennial or biennial flowering plant that is ideal for use in cottage gardens, perennial beds, or containers. The flowers come in many vibrant shades and are attractive to pollinators like butterflies, bees, and hummingbirds.

Planting sweet Williams in late spring will usually produce flowers the following year, although some new cultivars bloom in the first year you start the seeds early enough.

Research suggests that sweet Williams are mildly toxic to pets and people.

 Botanical Name Dianthus barbatus
Common Name Sweet William, bearded pink
 Family Caryophyllaceae
 Plant Type Herbaceous, Perennial
 Mature Size 1-2 ft. tall, 0.5-1 ft. wide
 Sun Exposure Full sun, part shade
 Soil Type Moist, Well-drained
 Soil pH Acidic, Neutral, Alkaline
 Bloom Time Late Spring, Summer
 Flower Color Red, Pink, White, and Bicolors
Hardiness Zones 3-9, USA
 Native Area Europe
 Toxicity Toxic to pets and people

Sweet William Care

Providing you locate them in a filtered sun position with rich, well-drained soil, you should have a thriving collection of sweet Williams. They readily self-seed each year with optimal growing conditions, so you will likely have a fresh batch of beautiful flowers to admire every summer. Space your sweet Williams about 8 inches apart if you are growing them as bedding plants to allow for the dense foliage that appears during the first year.

Sweet Williams plant with circular and frilly pink and white flowers in sunlight

The Spruce / Gyscha Rendy

Sweet Williams plants with pink, white and red circular flowers in sun lit garden

The Spruce / Gyscha Rendy

Sweet Williams plant with circular pink and light pink flowers clustered together

The Spruce / Gyscha Rendy

Light

Unless you live in a hot Southern region, your sweet Williams will appreciate a full sun position. They can tolerate light shade, but too much shade can result in the plants becoming overly leggy and floppy. In hot regions, some afternoon shade is a good idea as this will help prolong the bloom time.

Soil

Sweet Williams tolerate many soil types, but they don't cope well with wet, heavy conditions. A well-drained, fertile, loamy site is ideal. The plants can survive in soils with various pH levels too, but often do best in a slightly alkaline one. Some growers add lime to the soil before planting.

Water

Water your sweet Williams regularly through the growing season, but take care not to over-water. Waterlogged conditions promote fungal diseases in this species. A moist but not saturated substrate is best.

Temperature and Humidity

For a flowering plant, the sweet William is relatively cold-hardy. It can survive light frosts, but deep freezes will result in the plant dying down. This species doesn't do well with high humidity, and temperatures above 85° Farhenheit can result in dormancy.

Fertilizer

Your sweet Williams will appreciate being fed with an all-purpose fertilizer every couple of months while they are growing.

Propagating Sweet Williams

Propagating sweet Williams from cuttings is possible. However, because these plants are short-lived, many people simply purchase cold-treated plants during the spring to grow them as annuals.

How to Grow Sweet Williams From Seed

Sweet Williams are relatively easy to grow from seed, but they don't typically bloom the first year. They can be sown into the ground in the late spring or early summer when there is no danger of frosts. They prefer cool temperatures of around 50-55 degrees Fahrenheit and consistently moist soil for germination. Temperatures above 65 degrees Fahrenheit can result in weak, leggy growth.

These plants don't like to be over-crowded, so, as the seeds germinate, thin them out so there is adequate air circulation.

If you want to see blooms in the first year of planting, you could try sowing the seeds indoors six to eight weeks before the last spring frosts. Harden them off and transplant them outside in cell packs or containers once the frosts have passed.

Common Pests & Plant Diseases

Fungal diseases like rust and crown rot can be a problem for sweet Williams if they are planted in poorly drained soils or overwatered. They are also attractive to slugs and snails.

How to Get Sweet Williams to Bloom

With their small clusters of flowers, sweet Williams offer a splash of color right through the summer. Under the right conditions, these biennials can bloom from May through to October in their flowering year. Their bright range of colors includes reds, pinks, whites, purples, and variegates. Some flowers are fragrant, but many cultivars are scentless. Their fringed and bearded petals are what gives them their alternative "bearded pink" name.

Ensuring your sweet Williams have moist but well-drained soil is crucial for healthy and abundant bloom production. Overly hot temperatures also impact flowering capabilities. Keeping on top of deadheading spent flowers will also encourage more blooms. However, stop deadheading in the late summer to encourage self-seeding for new plants the following year.

FAQ
  • Are sweet William's easy to care for?

    You might only get one flowering season out of these plants, but at least they are low-maintenance and easy to look after. Providing they get the right conditions, sweet Williams will provide you with a proliferation of blooms with minimal effort.

  • How long can sweet Williams live?

    Although technically short-lived perennials, these plants are usually grown as biennials. Generally, they will only produce foliage during their first year of growth and then an abundance of blooms in their second year before dying at the end of the bloom season. Occasionally, they will bloom again for a third season.

  • Do sweet Williams make good cut flowers?

    This species is a popular cut flower because it is long-lasting and has a strong stem and large, attractive flower heads. Healthy cut flowers can last several weeks.

Article Sources
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  1. University of California Agriculture, and Natural Resources. “Toxic Plants (by Common Name).” Ucanr.edu. N.p., n.d. Web.