Sweet William
Dianthus barbatus · Caryophyllaceae
Flat-topped clusters of fringed flowers in pink, red, white and bicolours, with a clove scent, in late spring. A biennial that seeds itself year after year.
- Size
- 18 in tall, 12 in wide
- Zones
- 3 to 9
- Light
- Full sun to part sun
- Flowers
- Late May to late June
- Pets
- Toxic (mild)
- Job in a bed
- Drift
A bed built around sweet William
The planner designed this bed around sweet William when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why sweet William stands where it does.
The plants
- 1 Sweet William × 13, pink
- 2 Winter heath × 5, white
- 3 Sea thrift × 6, pink
- 4 False sunflower 'Summer Sun' × 3, yellow
- 5 Brown-eyed Susan × 8, yellow
- 6 Silver sage × 1, silver leaves
- 7 Hardy gladiolus × 5, pink
- 8 Daffodil × 7, orange
Why this plant
- The only dense clusters. The others are bells, globes, daisies and others. Shape reads at a distance, where colours blur.
Why here
- In the middle. At 18 in it is the step between silver sage (12 in) in front and false sunflower 'Summer Sun' (3½ ft) behind: each is seen over the one before.
- A step in the back row. Next to hardy gladiolus (2½ ft) and brown-eyed Susan (4 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 13 plants in 3 groups (5, 5 and 3). Seen again further along, the same plant ties the bed together.
Why now
- In flower for five weeks. From late May to late June.
- Fills a gap. For one of those weeks nothing else on the plan is in flower.
Planned as a cottage garden: 36 of the 36 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. The most in flower at one time is 3 kinds, from late May. The back corners are held by brown-eyed Susan and false sunflower 'Summer Sun', the tallest plants on the plan.
The planner's own design check: 14 Excellent, 3 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where sweet William goes in a border
At 18 in it belongs at the front of a bed. In the planner's ten height classes it is short (12 to 18 in).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
The traditional filler for the gap between spring bulbs and summer perennials. Let it seed and it will keep itself going; the colours mix without clashing because they share the same crimson base.
- Cottage gardens
- Cut flowers
- Filling gaps between perennials
What to plant with sweet William
Plants recorded as good partners for it, and what each pairing does:
- Lady's mantle: red against green, opposite each other on the colour wheel, if you choose those colours, in flower together for five weeks.
- Peony: in flower together for four weeks, from late May; tall enough (3 ft) to stand behind it.
- Foxglove: in flower together for four weeks, from early June; bold leaves against its medium ones; tall enough (4 ft) to stand behind it.
Questions about sweet William
Does sweet William need sun or shade?
Sweet William grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).
It wants ordinary well-drained soil, rich in organic matter, and a good soak in dry spells.
What zones does sweet William grow in?
USDA zones 3 to 9. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does sweet William flower in my zone?
In zone 5 it flowers late May to late June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 3 | Mid June to early July |
|---|---|
| Zone 4 | Early June to early July |
| Zone 5 | Late May to late June |
| Zone 6 | Late May to late June |
| Zone 7 | Mid May to late June |
| Zone 8 | Early May to late June |
| Zone 9 | Early May to mid June |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should sweet William be planted?
10 in (25 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 12 in (30 cm), so a group knits into one patch.
It grows 18 in (45 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many sweet William plants do I need?
At 10 in apart, set out in staggered rows:
- 17 to fill 10 square feet (about 1 m²)
- 13 for a single row 10 ft (3 m) long
- 55 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used 13 in three groups.
Is sweet William poisonous to dogs and cats?
Yes: mild toxicity to people, dogs, cats and horses. May cause mild stomach upset if eaten. Handling the plant can irritate skin.
Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like sweet William?
These come closest to doing what sweet William does, and no toxicity is recorded for them:
- Hairy beardtongue: the same job in a bed, the same size and the same flowering time; lavender, not pink, wants dry soil.
- Speedwell 'Red Fox': the same job in a bed and the same colour; 4 in shorter, flowers late June to mid August.
- Balloon flower: the same job in a bed and the same colour; belongs in the middle, not at the front, 6 in taller.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat sweet William?
Mostly not. NC State lists it as resistant to deer and rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
Will sweet William spread?
It seeds itself about; the risk of it taking over is moderate. Short-lived, but keeps going by self-seeding. Thin or move seedlings where they are not wanted.
What flowers after sweet William?
Sweet William is over by late June. These start as it finishes and carry the same spot on, so it never goes flat:
- Black-eyed Susan: from mid July to mid September, 24 in tall.
- Butterfly weed: from late June to early August, 24 in tall.
- Daylily: from late June to early August, 2½ ft tall.
What does sweet William look like in winter?
Sweet William dies down, but leave the stems standing: the seed heads stand through the winter, and songbirds eat the seed. Cut them down in early spring, before the new shoots come.
Is sweet William good for bees and butterflies?
Sweet William is visited by bees, butterflies, moths, hummingbirds and songbirds.
More Dianthus
- Carthusian pink Dianthus carthusianorum
- Cheddar pinks 'Bath's Pink' Dianthus gratianopolitanus 'Bath's Pink'
- Cheddar pinks 'Firewitch' Dianthus gratianopolitanus 'Firewitch'
- Cheddar pinks 'Tiny Rubies' Dianthus gratianopolitanus 'Tiny Rubies'
- Cottage pinks Dianthus plumarius
- Cottage pinks 'Mrs Sinkins' Dianthus plumarius 'Mrs Sinkins'
- Dianthus 'Kahori' Dianthus 'Kahori'
- Fringed pink Dianthus superbus
- Maiden pinks Dianthus deltoides
In these guides
- Deer-resistant perennials for full sun
- Rabbit-resistant plants
- Garden plants toxic to cats
- Garden plants toxic to dogs
- Plants for hummingbirds
- Plants for butterflies
- Plants for bees
- Plants that feed garden birds
- Plants for a white garden
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial
- Size
- 18 in (45 cm) tall, 12 in (30 cm) wide
- Plant
- 10 in (25 cm) apart
- Height class
- Short (12 to 18 in)
- Place in the bed
- Front
- Flowers
- Late May to late June; dense clusters; pink, red, white, purple
- Leaves
- Medium texture, herbaceous; green
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 3 to 9
- Light
- Full sun, part sun
- Soil
- Rich, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Caryophyllaceae
- Comes from
- European Mountains (Pyrenees, Carpathians, Balkans)
- Attracts
- Bees, butterflies, moths, hummingbirds, songbirds
- Stands up to
- Deer, rabbits, heat, humidity
Checked against NC State Extension, ASPCA poison lists and VASCAN (plants of Canada). Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.