How Tall Are Sweet William Flowers?

Growth Habit

• You can grow Sweet William in U.S. Department of Agriculture plant hardiness zones 3 to 9. Although Sweet William is technically a perennial, it degenerates quickly as after its second year so it is commonly described a short-lived perennial or biennial. If you grow it from seed as a biennial it will grow leaves the first year and blossom the second year. Many new annual cultivars will bloom from seed the first year if you sow them early enough. You can sometimes buy nursery seedlings in early fall to plant for blossoms early the next spring or cold-treated plants in spring for blossoms the same year

Use

• Sweet Williams like moist soil and lots of sun, but it you live in an area with extremely hot summers, plant them where they can get partial sun. They look good in mass plantings or grown as a border. Dwarf cultivars are good choices for a rock garden.

Planting Date

• You’ll have to wait until the danger of frost has passed before you sow Sweet William seeds. They germinate best when the soil temperature is 60 to 70 degrees. Plant these small seeds close to the surface, about 1/16 inch deep, and they should germinate in 14 to 30 days. If you sow the seeds of an annual cultivar, remember that it will take 60 to 90 days for them to bloom from the time you sow the seeds.

Perennial Reseeding

• While a short-lived perennial will linger in your garden, it will decline rapidly after a couple of years. However, if you live in a climate with mild winters and good growing conditions, Sweet William will reseed itself each year, so older plants replace themselves with young, vigorous plants, giving you more blossoms. To encourage perennial reseeding, remove spent flowers and remove large plants.