Sweet William.

At a glance

Care level

Easy

Plant type

Herbaceous perennial

Light

Full sun to partial shade

Indoor light

Direct sun

Water

Every 3 to 7 days

Mature size

1 to 2 feet

Growth rate

Medium

Hardiness

USDA 3 to 9

Bloom time

Late spring to early summer

Care

Plant these in well draining soil and keep them consistently moist but not soggy. Watch for yellowing leaves which often indicate poor drainage or overwatering. Deadheading spent blooms will encourage the plant to produce more flowers throughout the season.

Watering

Keep the soil evenly moist but avoid letting the roots sit in standing water.

Feeding

Apply a balanced liquid fertilizer once a month during the active growing season.

Pruning

Regularly remove faded flowers to promote continuous blooming.

Repotting

Repot only if the plant becomes root bound or if you need to refresh the soil.

Soil

Well draining, fertile soil

Soil pH

Neutral to slightly alkaline

Temperature

-40 to 30°C

Humidity

40 to 60%

Drought tolerance

Moderate

Lifespan

Short-lived perennial, typically 2 to 3 years.

Fragrance

Strong

Deer and rabbits

Moderate

Safety

People

This plant is generally considered non-toxic, though it may cause mild skin irritation in sensitive individuals.

Pets

This plant is considered mildly toxic to cats and dogs if ingested.

Children

The plant is not considered a significant risk to children, but ingestion of any garden plant should be discouraged.

Contact allergens

The foliage can cause mild contact dermatitis in sensitive people.

Airborne allergens

Pollen is generally not a significant trigger for hay fever.

Edibility

While the flowers are technically edible, they can cause mild digestive upset if consumed in large quantities.

How to identify it

• Clusters of small fringed flowers
• Lance shaped green leaves
• Sturdy upright stems
• Vibrant colors including pink and red

Height

0.3 to 0.6m

Spread

0.2 to 0.3m

Leaves

green, blue-green, semi-evergreen

Flowers

pink, red, white, purple, 1 to 2cm

Problems to watch for

• AphidsCommon
• RustCommon
• Botrytis BlightUncommon
• Leaf SpotUncommon
• Root RotUncommon
• Slugs and SnailsUncommon

Growing it

Propagation

seed, cuttings, division

When to plant

spring, autumn

Overwintering

Apply a light layer of mulch to protect the crown from extreme temperature fluctuations. Ensure the soil does not stay waterlogged during winter months.

In containers

It grows well in containers, provided the pot has excellent drainage and is at least 20 centimeters deep.

Plant in groups to create a dense display that helps suppress weeds around the base.

Grows well with

• Lavender · They share similar requirements for sun and well-drained soil.
• Catmint · Its blue flowers provide a nice color contrast to the pinks and reds of Dianthus.

Similar species

• Cheddar Pink · A smaller, more mat-forming relative.

Science

Family

Caryophyllaceae

Genus

Dianthus

Order

Caryophyllales

Class

Magnoliopsida

Native range

Southern Europe and parts of Asia.

Conservation

Not of conservation concern.

It thrives in well-drained, alkaline soils and open, sunny meadows.

Value to wildlife

nectar source

Pollinators

bees, butterflies, moths

Uses

cut flowers, cottage gardens, borders, containers

Taxonomy resolved against GBIF.

Questions people ask

Is Sweet William a perennial?

It is technically a short-lived perennial often treated as a biennial.

How do I encourage more blooms?

Deadheading spent flowers will often encourage a second flush of blooms.

Where the name comes from

The scientific name Dianthus comes from Greek meaning divine flower, while the common name Sweet William likely honors a historical figure or refers to its pleasant scent.

Good to know

• It is often grown as a biennial, blooming in its second year.
• The flowers are known for their clove-like fragrance.
• It has been a popular garden plant since the 16th century.

Also in

• Plants toxic to cats and dogs