Sweet William

Sweet William: how do you recognise it?

Habit

Upright, clump-forming plant 30–60 cm tall and 20–30 cm wide; there are also dwarf varieties of 15–20 cm.

Leaves

Lance-shaped, 4–10 cm long, green, in opposite pairs; broader than in most other pinks.

Flowers

Small flowers of 1–2 cm with toothed petals, gathered in dense, flat heads, in June and July.

Colour

White, pink, red, deep red and purple, often with an eye, an edge or zones of another colour.

Scent

Lightly spicy, rather like cloves, especially on warm evenings.

Flowering: June–July · Sowing: May–June · Plants: September–October · Pruning: July

Why grow it?

• A classic, lightly scented cut flower that lasts well in a vase.
• Flowers in June–July, bridging the gap between spring and summer flowers.
• Bees, bumblebees and butterflies visit the flowers.
• Colourful and easy: sow in summer, flowers the following year.
• Fits perfectly in a cottage garden, a cutting garden or a romantic border.

Sweet William: where does it grow best?

• Full sun for sturdy stems and the best flowering.
• Free-draining soil: sand, loam or clay; neutral to chalky.
• Normally moist; wet feet in winter make the rosettes rot.
• Plant 20–25 cm apart.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Neutral or chalky

Moisture

Normal

Size

0.5 m tall, 0.3 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Roses: A classic cottage-garden pairing, flowering at the same time.
• Lupin: Tall, upright spikes behind the flat heads.
• Love-in-a-mist: An airy blue among the red and pink heads.
• Lady’s mantle: A soft, yellow-green edge at the front.

Sweet William: when and how to plant it?

Plant in September–October.

1. Sow in May–June in a seedbed or seed tray and cover the seed lightly.
2. In July, move the seedlings to a nursery bed or small pots, 15 cm apart.
3. Plant out in September or October where they are to flower, in limy, free-draining soil.
4. Set the rosettes at the same depth as before, not deeper, 20–25 cm apart.
5. Water in straight away and firm the soil well.

Care

Watering

Young plants in dry summer weather; after that only in long dry spells, at the base.

Feeding

Some compost in spring. Too much feed gives floppy stems.

Lime

On acid soil, scatter some lime around the plants in autumn.

Support

Rarely needed; tall varieties in a windy spot appreciate a few twiggy sticks.

Picking

Cut for the vase when a third of the flowers in the head are open.

Tip: A biennial: sow in May–June and plant out in September where it is to flower, in limy, free-draining soil. The fragrant heads make lovely cut flowers.

Sweet William: when to prune it?

Pruning months: July.

When: After flowering, in July, cut back the flower stems. No other pruning is needed.

How:

• Cut the spent stems back to just above the leaf rosette.
• If you want it to self-seed, leave a few heads until the seed is ripe.
• If you cut it back after flowering, it often flowers for a second year; otherwise, replace it.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

In May–June outdoors in a seedbed or seed tray. Germinates in 1–3 weeks. Plant out in September for flowers the following year.

Cuttings

In July–August, take 8 cm cuttings from non-flowering shoots in sandy cutting compost, to keep a favourite colour.

Self-seeding

Let a few heads set seed: the seedlings are not always the same colour as the parent plant.

Sweet William: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C: no protection is needed in Belgian winters.
• The green rosettes stay in place all winter.
• Heavy, waterlogged soil is more dangerous than frost: make sure drainage is good.
• In pots: a drainage hole and a spot out of the rain, against a wall.

Diseases and pests

• Rust: Brown or orange pustules on the leaves. Remove affected leaves, water at the base and do not plant too closely.
• Stem rot: The rosette turns brown and soft at the base, especially on wet soil. Plant in a free-draining spot and not too deep.
• Slugs: Attack young rosettes in autumn and spring. Check in the evening and pick them off.
• Aphids: On young shoots and buds. Hose them off; natural predators usually deal with them.

Through the year

• March: Compost around the rosettes.
• May: Sow in a seedbed or seed tray.
• June: Flowering starts. Pick for the vase. Sow.
• July: Flowering. After flowering, cut back the flower stems. Transplant seedlings.
• August: Take cuttings. Water young plants in dry spells.
• September: Plant out where they are to flower.
• October: Last planting. Lime acid soil.

Edible and useful

Not edible. Sweet William and China pink are mildly poisonous: eating them can cause vomiting, stomach ache and diarrhoea, in children as well as in cats and dogs, and the sap can irritate sensitive skin. Not all pinks are the same: the fragrant petals of common pink, Cheddar pink and large pink are used in the kitchen, but not those of these two. So only use flowers when you are sure which pink they come from, keep a vase of pinks out of reach of cats, and do not let children put flowers in their mouths. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The name Dianthus comes from Greek and means ‘flower of Zeus’ or ‘divine flower’.
• Sweet William was already grown in European gardens in the 16th century.
• It is not certain who the ‘William’ in Sweet William refers to: there are several stories.