How to Protect Sweet William

Red sweet William in a spring garden. image by H.B. Dean


Sweet William is a part of the genus Dianthus, which includes many species of annual, biennial and perennial flowers. They range in height from 6 to 18 inches tall, producing flat, round petals that are 1 inch across with fringed edges in pink, white, red or multiple colors. Sweet William are easy to grow, but require protection from poor soil, over-fertilizing and pests.

Step 1

Amend the soil about one month before planting sweet William. They thrive in rich, well-draining soil. Dig up the soil and incorporate generous amounts of well-rotted compost or manure. If the soil is heavy clay, add peat moss as well.

Step 2

Apply a complete plant food in the early spring, when the begin active growth begins. Be careful not to over-fertilize, as these flowers are sensitive to excess nitrogen, which can cause brown leaf tips to develop.

Step 3

Protect sweet William from aphids and slugs. Spray the flowers with malathion to treat for aphids. Spread a circle of crushed eggshells or diatomaceous earth to prevent slugs from attacking the flowers.

Things You'll Need

  • Shovel
  • Well-rotted compost or manure
  • Peat Moss (optional)
  • Complete plant food
  • Malathion
  • Eggshells or diatomaceous earth


  • Burpee Complete Gardener; Barbara W. Ellis, Editor; 1995

Who Can Help

  • American Gardening Association: Dianthus
  • University of California Statewide Integrated Pest Management Program: Snails and Slugs
Keywords: biennials, Sweet William, protection flowers

About this Author

After attending Hardin Simmons University, Kay Dean finished her formal education with the Institute of Children's Literature. Since 1995, Dean has written for such publications as "PB&J," Disney’s "Family Fun," "ParentLife," "Living With Teenagers" and Thomas Nelson’s NY Times bestselling "Resolve." An avid gardener for 25 years, her experience includes organic food gardening, ornamental plants, shrubs and trees, with a special love for roses.

Photo by: H.B. Dean