What should I do about my citrus tree with new shoots appearing yellow
and shrivelled? The tree has been covered in creeping vines - which I
have removed, but it looks sick.
It is very difficult to do a proper analysis and diagnosis of the problem without being able to see the problem and investigate a bit further.
The yellowness could have been caused by the creeper covering the tree and shading it out for some time.
The symptoms could have been caused also by a virus, e.g. transmitted by aphids.
Check for any insects on the tree (leaves, branches).
It could also be a nutritional problem, especially if only one age class of leaves seems to be affected, e.g. problem appears only in the young leaves.
Often the pH of the soil is too high (commonly leading to iron deficiency) or too low. Any additions of the nutrients which appear to be missing will not be effective as long as the pH remains out of balance.
I would be tempted to try a weekly feeding with a liquid fertiliser made from one of the commercial fish based sprays and a tea of seaweed (half a bucket full of washed seaweed from the beach, fill up with water, put a lid on, stir every day, let ferment for a total of two weeks, dilute 1:1 with water for feeding the roots of the tree; fish fertiliser concentrate may be added). A check for the pH of the soil seems recommendable as well.
Citrus trees also generally need a fair amount of water to take up the larger amounts of nutrients they require.