Kitchen sink remedies

Gardeners are always looking for simple ways to treat problems so here are a couple that you might like to try.

1: Petal blight is a constant source of frustration for people who love camellias. I’ve written about the problem before but at the camellia show in Tauranga at the weekend heard of a “remedy” that may be worth trying.

Sprinkle soap powder (laundry powder) underneath the camellia, the theory being that it kills the fungus (Ciborinia camelliae) before it can release its spores (upwards) to continue its life cycle on the flowers (which take it back down to the soil when they drop).

Petal blight on a camellia. Photo: Sandra Simpson

Long-time camellia grower and breeder Ailsa James believes it’s worth a try, although notes that if your neighbours have infected plants it will keep blowing over the fence. She has also heard that there is an onion fertiliser in Germany that kills the fungus but  it’s not available in New Zealand.

2: Once you’ve pruned your roses this year, mix up one-quarter of a teaspoon of Condy’s Crystals (potassium permanganate) to a litre of water and spray the branches and surrounding soil – the idea being that this is a mild steriliser. You can also spray the foliage when it emerges. Wally Richards has written extensively on its use, not just for roses but in cases of brassica club foot too (a stronger mix is suggested for that).

Please note that this mixture will be very purple and may stain clothes (it did come off my hands, where it had turned brown, after a few washes).

Camellia petal blight

Someone asked me today if the local camellia show was on for two days – it used to be, but the ravages of camellia petal blight (Ciborinia camelliae) convinced the organisers a couple of years ago that a single day was preferable.

“People come to see the best flowers we have,” Western BOP Camellia Society president Caroll Anderton said. “They don’t want to see flowers that have ‘gone off’ and neither do we. The flowers look good for the first day, but not great on the second.”

A society member who used to live on the Kapiti Coast, which had the fungal disease, said that when he moved up this way to retire, he checked whether the airborne blight had reached the Western Bay of Plenty. When he found out it hadn’t, he responsibly left all his camellias behind and started again.

There’s nothing much to be done once you’ve got the the blight that creates brown splotches on camellia petals and shortens the life of the flower, although I’ve heard that some research is going on in New Zealand.

It was first described in Japan in 1919, the United States (1939), New Zealand (in Wellington in 1993) and parts of mainland Europe. It was found in Britain in 1999 and is now present in southern England, including at RHS Garden Wisley. Read more from the RHS here. Apparently Australia does not have it.

The American Camellia Society is downbeat about the problem and besides recommending exclusion (not very practical) offers a couple of other suggestions. Remember that the seasons are reversed. This website offers some organic treatments. There are no fungicides available to treat the problem.

Abbie Jury has some background on the arrival of the blight and its consequences for New Zealand and the Science Behind Your Garden website digs a bit deeper again.