Iris chlorosis

[John85]

A friend has a problem with his Iris germanica.
The leaves turn pale green then yellowish before drying.
It doesn't look at all like leaf spot although some weakened plants get it later on.
It looks more like a nitrogen deficiency but the hole plant is not affected only parts of leaves.
The soil is arich well drained loam.
The rhizome looks healty.
Any idea what it could be???

[Steve Garvie]

Could it be Bearded Iris Mosaic Virus (ISMV=Iris Severe Mosaic Virus)?
It would be worth posting an image of the leaves.
Are there any colour breaks/aberrations of the flowers?

[John85]

I hope it is not ISMV as my friend has a huge collection but I think it isn't a virus infection as there is a sharp limit between the yellowish area and the healty one.
Sorry no image as i hadn't my camera with me yesterday when I visited my friend.
It is the very first time this happens so no idea if it will affect the flowers.
Thank you for your suggestion.

[ArdfearnAli]

Hi there,
           It could be a simple deficiency in the soil. I had similar problems a few years ago with hostas. The young leaves grew then went very pale and started to wither and dry out at the tips going brown. I had a fertiliser rep at the nursery and he reckoned it was Calcium deficiency? I fed them with a foliar feed that contained calcium and it cured the problem. It didn't fix the damaged leaves but the new ones were fine. It is something to do with plants needing calcium for strength in the cell structure of the leaves. A deficiency causes thin leaves without much substance which tend to dry out and die back. I would try a good liquid feed that contains trace elements as a foliar spray . There is Calcium Nitrate available but I think its more agricultural. If you look at the back of liquid feeds it should show the ingredients including trace elements. I have also seen straight trace elements made by companies like Chempak but not sure if they contain calcium?

Hope its a cultural problem and not virus

Alasdair