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Beating the Blight

This article was first published on 05 May 2016.

Camellia in the Botanic Garden

Camellia in the Botanic Garden

Photo by the Otago Daily Times

The Bad

In the 1990s a fungal disease affecting only camellias arrived in New Zealand.  As its name suggests, camellia petal blight, Ciborinia camelliae, damages only the flowers of camellias.  It has become well established throughout the country.  There is no control.

The Ugly

At the beginning of winter, prompted by humid weather, tiny mushrooms release billions of spores that can travel on the breeze for several kilometres.  On contact with a camellia flower a spore infects the petal.  Initially just a brown spot, the infection spreads over several days, eventually turning the entire flower dirty brown.  When the infected flowers fall to the soil, the fungus develops into a hardened food-storage structure, growing beneath the surface.  This “sclerotia” produces mushrooms and is viable for a number of years.

The Good

Despite all this, camellias have great landscape value such as their luxurious, dark green, shiny foliage.  The beautiful autumn ‘sasanqua’ camellias flower now before the camellia petal blight season begins.  They are growing at Dunedin Botanic Garden in beds at the approach to the café and a Camellia Collection pamphlet from the information centre will help you locate others. 

Many ‘sasanquas’ have a light fragrance and attract honey bees and nectar-feeding birds.  Small, delicate leaves make them an excellent choice for hedging and espaliering.

To improve the display of camellias during the blight season, twist off the damaged blooms regularly.  There is no need to treat them in any special way because of the established nature of blight.

Marianne Groothuis is the Camellia and Theme borders collection curator at the Dunedin Botanic Garden.