Back to growing guides
S
FlowersHardyBiennial
Sweet William
Sweet William is a compact scented plant usually grown as a hardy biennial for dense heads of flowers in late spring and early summer. It suits edging, cottage-style borders and cutting gardens, and often gives stronger colour impact when planted in groups.
Basic information
Category
Flowers
Lifecycle
Biennial
Hardiness
Hardy
Planting partners
0 companions · 0 crops to avoid
Growth profile
Germination window
7–14 days
Germination temperature
15–18 °C
Plant spacing
25 cm
Row spacing
35 cm
Sowing depth
0.5 cm
Height
45 cm
Spread
25 cm
Calendar
JJan
FFeb
MMar
AApr
MMay
JJun
JJul
AAug
SSep
OOct
NNov
DDec
Sow Indoors
Sow Outdoors
Plant Out
Flowering / Harvest
Timings based on average frost dates in the UK. Sign up to set your frost dates.
Care tips
Raise sweet williams one season for flowering the next, or buy young plants for autumn planting so they establish before winter. Grow in sun with good drainage, remove spent heads for neatness, and renew plantings regularly because older plants lose vigour.
Common pests
Slugs, aphids, rust, crown rot in wet sites.
Companions
No companion crops have been added yet.
Don’t grow with
No crops to avoid have been added yet.