Rose: Bullheading (cold damage)

categories: Flowers Ornamentals Rose Rose Diseases

revision date: 2023-02-07 12:00

Rose bud against a black background exhibits a flat-topped appearance.
Rose bullhead
Photo by: R.S. Byther


Bullheads are the most prevalent when temperatures dip to 53-59 degrees Fahrenheit during early flower development. Low temperatures appear to alter metabolic activity, which results in the abnormal appearance of buds and resulting flowers. Flower buds exhibit a flat-topped appearance and weigh more than normal buds with a pointed tip. The number of short petals and petaloids increases, as well as the amount of secondary florets near the bases of flowers. Baccara, Talisman, and cultivars belonging to the Columbia family are especially susceptible.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • In spring, prune bullheads and allow new flowers to develop in warmer weather.
  • Do not plant in cold areas, and protect roses from frost.
  • Do not fertilize, prune, or water heavily late into the season. This can encourage growth that cannot acclimate well in autumn.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • None recommended