You don't need to get rid of them - even if the plants are shrivelled back to nothing, the roots will be fine and they should grow again. Next time you notice powdery mildew, make up a solution of 1 part milk to 9 parts water in a spray bottle and spray thoroughly until run off, under the leaves and on top if possible. You could try it now, but it may not do much if the plants are seriously affected. Either that or a fungicidal spray.

Powdery mildew is always about in the air, not in the soil, so you don't need to worry about that.

Well I never heard of that Bamboo, thankyou....

Thank you both for asking and answering the question. I knew that powdery mildew did not kill plants Bamboo but I will take a note of the milk and water remedy as I prefer not to use any chemicals if possible. I cut off the affected bits and the following year the plants were fine.

Thanks very much. I've rescued the plants I'd got rid of. I'm really grTeful for the advice Bamboo as there were actually quite a few plants with good roots.

Full cream milk by the way!

Thats what they'll get here O'boggy, lol...

They had better go on a diet in our garden Owdboggy as we only buy skimmed milk.

Erm sorry Owdboggy, no, it doesn't have to be full cream milk, it can be skimmed or semi skimmed too - its the lactose content in the milk that does the job, so the cream factor is irrelevant.

Tried it with all three and the full cream one was the only one to work, sorry. Had to buy it special too as we don't drink the stuff normally. Like the fungus I am lactose intolerant.

I've tried with skimmed and semi skimmed - I need to try again, because I thought the semi skimmed worked better, but it could just have been that I sprayed more thoroughly, getting under the leaves and all the stems too. The research indicates cream content is irrelevent though.

Perhaps it is easier to see where the milk has gone on top the leaves when it has more cream content?

No idea, think I was just concentrating more - they recommend the use of non fat or low fat milk as much as anything because, if its got cream in it and its summer, the cream goes rancid and your plant is smelly...

Think I will stick to Copper sulphate then.