I have a green Cordyline in a large clay plant pot. Up until the last few days it was looking great. Now the leaves are turning yellow and slightly mottled. The plant must be around three years old and I have not had any problems with it before. I gave it a feed of Multigrow a couple of weeks ago.

Can anybody tell me what could be the problem?

. Hi, Lintama, I grow lots of Cordyline australis, if you get this problem (a type of rust) spray with Dithane 924 and this will clear it up. Professional growers of cordylines use this as a routine spray to keep the plants green and healthy. Just a little tip when using Dithane powder (which is notoriously difficult to mix ) use a coffee jar with an inch of water in it , tip the powder in, put the top on and then shake vigorously to mix, then pour into sprayer.
best of luck lannerman.

OK Thank you Lannerman. I had a friend tell me it could be lack of nitrogen. Could this be the problem instead? I am not saying you are wrong of course, just trying out possibilities.

[quote=Lintama;846738]OK Thank you Lannerman. I had a friend tell me it could be lack of nitrogen. Could this be the problem instead? I am not saying you are wrong of course, just trying out possibilities.

Hi, Lintama, Lack of nitrogen will not give you the 'mottled' effect you discribed just an overall yellowing, but I thought you said you had fed them?
Try the dithane anyway as I'm sure this will clear the problem, and it will not do any harm to give them a liquid feed again as they are quite hungry.
best wishes lannerman.

[quote=lannerman;847152] Hi Lannerman,
Yesterday I gave the plant some bone meal and watered it in. Perhaps it would be best to transfer the plant into the ground where it will get more nutrient.
I gave it some Multi-Grow a couple of weeks ago but perhaps one application wasn't enough for it.

I will get some of the Dithane as you mentioned and see if it helps.

Will I need to remove all the yellowish leaves?

Thank you again.
Lintama

[quote=Lintama;847201] Hi Lintama, Bonemeal is OK but will not give very much nitrogen, I would feed with 'miracle grow' and as well as feeding the soil, also feed the leaves but do this in the evening when the sun is not on the plant, this will folia feed it and will naturally green up the leaves. The lower leaves on a Cordyline will go from yellow to brown as they die off as the trunk is formed, this is a natural process and the lower leaves should only be removed if they come away from the plant easily as if they are forcible removed before they are ready you could dammage the trunk. How big is this 'palm' and where abouts do you live as thiswill have a bearing!
Best wishes lannerman