When to Separate Sweet William

When to Separate

• Sweet william grows for only two years before dying, which means it has a biennial life cycle. Established sweet william plants can be separated for divisions in autumn of their first year or in the spring of the following year, depending on the climate. In very mild climates with little frost, separate sweet william in autumn since the divisions can be planted immediately in the garden and will be well established as individual plants by the following spring. In colder climes, it is best to separate sweet william in spring of the following year, after the last hard frost, when the plants are entering their active growth cycle.

How to Separate

• Few tools are needed to successfully separate sweet william plants, apart from a garden trowel and a hose. Before separating the plants, water them thoroughly with a hose to ensure the roots are hydrated and pliant. Measure out 3-square-inch portions of growth. Use a garden trowel to dig down around the sections to a depth of 4 inches. Lift the divisions and fill in the hole left by them. Plant each sweet william in a 6-inch square pot filled with soil or transplant them 6 to 12 inches apart in a sunny bed.

Care of Divisions

• While sweet williams typically require little care, newly divided specimens benefit from thorough watering after transplant. Water to a depth of 1 inch once a week to promote healthy growth, but allow the soil to dry in the top half-inch between waterings to keep them safe from fungal infections. Fall-separated sweet william plants that were transplanted into pots do best when overwintered in a cold frame or sheltered spot since they do not yet possess a viable root system and can be negatively impacted by cold, dry air.

When to Transplant

• Spring is the ideal time to transplant sweet william divisions, whether they were separated in spring or autumn and kept in pots for the winter. Wait until one to two weeks after the last hard frost to transplant sweet william into the garden, preferably once the soil warms to 68 degrees Fahrenheit. Space the divisions 6 to 12 inches apart. Make sure the base of the stems is level with the surrounding soil and that the soil is light and well-draining.