I have 40 'Sunset' lilly pillies in a hedge - they're about 18 months old. I have an ongoing problem that I can't figure out and my local nursery and grower is baffled. The entire mid section of each plant is discoloured (the leaves). It's not a coating - the actual colour of the leaf has changed to brown.

The second problem is that random branches (on a different plant each time) keep dying. It's very sudden each time...there's no warning and then all of a sudden an entire branch (sometimes a big one, sometimes small) just up and dies.

It might sound strange, but other than this (!!) the plants look really healthy and there's plenty of new growth.

So far we've tried treating them with White Oil and Yates Pyrethrum Insecticide and nothing has helped.

We water them regularly, they don't have wet feet and most of the plants are in full sun (some get shade). They get tip pruned in Spring/Summer although they weren't pruned for the first 12 months after planting. There are black ants on some of them. I don't see any evidence of insect activity or bumps on the leaves (just discolouration).

Can anyone help with this?

L