Canna 2012

You're right, Pete, and it has worried me. But I had a little correspondence with RHS and also Harts about this, sending pics of the leaves, just in case. RHS said that the streaking doesn't have to be a virus but that's what everyone jumps to the conclusion of. They say they've had a lot of their own cannas suffering from streaking but don't put it down to virus but the awful weather we've had. They also said that there are several different virus out there affecting Canna and others but they are hard to diagnose and that the effects were different regarding the severity. But any plants that have streaking with distorted, weak leaves should be binned. Harts were a little more hard nosed and said from their view as a top commercial grower and retailer they would obviously not sell such plants [I bought this Yara from Harts]. Whatever their opinion I will be binning this Yara and a King Humbert, the last just not performing well at all. That was one of the reasons I asked in an earlier post if anyone would be buying new varieties and rhizomes.

 

Well, I feel more reassured after the feed back from the RHS, Pete, I must admit. But Philip Stanley at RHS said that they would be destroying all their affected Cannas whatever the reason for the streaking as they have to maintain the highest standards. But, he did say, that many amateur gardeners destroy their Cannas out of sheer panic and myth and that really a lot of them were fine apart from the streaking. He also said that some gardeners wouldn't tolerate plants that were growing absolutely fine apart from the marking in the belief it was the Virus
The trouble is there are so many biting/sucking insects out there that there's always going to be some disease transference year after year. I guess it all comes down to keeping an eye on things and then deciding if you're going to bin a plant or not. As I said I will be binning at least one King Humbert and the Yara and just keep plodding on keeping a yearly check on them. I did contemplate spraying the Cannas with a systemic insecticide from early on but it would be of no use as the insect will have injected fluid into the plant before the insecticide was of any use.

 

My problem with that, Kristen, is that I use very little insecticide due to the adverse effects on the beneficial insects. Since I've employed a minimum chemical regime in the garden the numbers of Butterflies, Hoverflies and Bees has shot up. Aphids of all kinds will be brought in by the wind whatever level of spraying insecticide I do, and they'll be doing the damage before I even get up in the morning and get the time to find them. So it has to be a damage limitation exercise knowing that I'm going to lose a few plants here and not killing off beneficial insects.

 

This is Canna Durban flowering for the very first time.





Canna Ambassador still flowering nicely.

 

Mowgley, I'm not an expert on Canna but I think your foliage problem with Cleopatra is not the virus.

 

This is what the guy at RHS said.....the existence of the Virus has become a bit of a tale to be told the kids at night. Anyone owning a Canna seeing a bit of discolouration or lack of growth immediately diagnoses the worst kind of virus. They reckon there are around 30 or so viruses that can affect the family of Cannas and some other plants. Only 3 of those have serious effects on Cannas, while the others only have a mild effect. But as JWK says seeing a Canna not looking as good as you would like it doesn't mean it's the Virus. It comes down to the fact that Cannas like all plants get attacked by biting and sucking insects throughout the year and injected with all sorts of bacteria and viruses but there's a lot of other diseases out there than can knock the plant sideways without it being the Virus.