Camellia Petal Blight

Disease and Pests Insects & Pests Ornamental Camellias

Camellias are the most enjoyable plant I can think of.  They bloom in the fall and winter when the rest of the garden is fast asleep.  The gardens become ablaze with color and it is impossible to sit in your comfy chair inside by the fire.  You feel the need to get outside and enjoy them despite the weather.  So you grab a basket, head out to the garden to pick that perfect bloom only to find that there are these brown blotches all over your blooms?  WHAT is this you say as you frantically search for a bloom that is fresh with no spots.

This condition is called Petal Blight.  It occurs when cooler temperatures are followed by warmer, humid weather.    The culprit, the fungus Ciborinia camelliae Kohn, affects only the flowers of Camellia.  It starts as small spots or flecks but quickly spreads throughout the entire flower blossom.  When the flowers fall to the ground and decompose, the fungus enters the soil and usually lies dormant until the next year.  As the weather begins to show a slight change from cold to warm, the fungal spores are released from the ground, float up in the air and land on opening flowers where they penetrate the petals and the process begins again.  Depending on the climate, it can occur as early as December and as late as March or April.

The use of topical fungicide has been largely unsuccessful due to the nature of camellias opening periodically over a period of time.  Systemic fungicides that are taken up into the plant have also been unsuccessful.   Picking up all of your spent flowers before they decompose is an option but an unrealistic one in most cases.  Spores can travel for short distances so even if you are removing all of your blooms, if your neighbor is not, then it's not much help.

We have found that a fresh layer of mulch applied in late fall offers some help to make it more difficult for spores to get into the air.  It's not a cure, but it does slow it down.

Here are some suggestions if you want to get the most out of Camellias without Petal Blight.

  • Choose fall-blooming Camellias.  Petal Blight rarely occurs before the end of December.
  • Use Gibberellic Acid to apply to camellia blossoms to encourage early blooming to avoid Petal Blight.  This is done per flower and not for the entire bush.
  • For enjoying blooms indoors, pick your flowers as soon after opening as you can to lessen the chance of fungal spores.
  • Rake up or remove as many blossoms as possible.  Destroy blooms by burning if possible.  Don't use them in the compost bin.
  • Apply a fresh layer of mulch in the fall.


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