How to grow Sweet William

Dianthus barbatus

Full Sun
OR
Partial Sun
High

Fertilize in Spring & Summer. Cut back after flowering.
Can be used as a cut flower.
Some gardeners use Sweet William as a biennial and pull it up after flowering the summer after planting out

Growing Sweet William from seed

Sow in mid summer, cover lightly.
Most dianthus require light to germinate. Well-drained neutral to sweet soil is appreciated.

Soil temperature should be kept higher than 10°C / 50°F to ensure good germination.

By our calculations*, you should look at sowing Sweet William about 49 days before your last frost date .

Transplanting Sweet William

Transplant three seedlings into 7cm pots and pot up as the plant establishes. Grow on in sheltered conditions and plant out in the flowering position at the end of the summer or early autumn.

As Sweet William is very hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.

Harvesting Sweet William

Can be used as a cut flower, lasts very well in a vase

Seed Saving Sweet William

Seed viability is five years.

How long does Sweet William take to grow?

These estimates for how long Sweet William takes to sprout, grow and harvest are from real observations from real gardeners, right around the world.

Days to Germination How long does it take Sweet William to germinate?: 8 days
Average 8 days | Min 5 days | Max 15 days (25)
Days to Transplant How long until I can plant out Sweet William?: + 39 days
Average 39 days | Min 17 days | Max 288 days (3)
Days to Maturity How long until Sweet William is ready for harvest / bloom?: + 138 days
Average 138 days | Min 34 days | Max 603 days (11)
Total Growing Days How long does it take to grow Sweet William?: = 185 days

When should I plant Sweet William?

Our when to plant Sweet William estimates are relative to your last frost date.

When to sow The number of days to sow Sweet William before or after your last frost date.: 49 days before Last Frost Date

Sweet William Etymology

The botanical epithet is from the Latin barbatus meaning “bearded”

Sweet William Folklore & Trivia

The Sweet William flower symbolises gallantry.
Dianthus barbatus was included in Catherine Middleton’s 2011 bridal bouquet, most likely due to its common name of “Sweet William”.

Other names for Sweet William

Dianthus, Sweet Williams, Dianthus barbatus, Green trick

Dianthus x barbatus, Dianthus barbatus L.