I have a row of 8 very large Eliocarpus eumundii trees (Eumundi Quandong) that were planted out from 200 litre bags 7 months ago and they are now at 5 metres tall. They originally flourished and have grown well but now have brown tips on their leaves. I read your article concerning this and believe the trees to be stressed, as they were planted into too small holes by the landscaper and the soil is a heavy clay. They have had good watering with good rainfall. Maybe too much water, if anything. What can be done to help these beautiful trees? They are too large to transplant. Thank you.
If your ground is holding water (i.e. you get a swampy yard after it rains), it is very possible that the plants are sitting in a bowl like hole that collects water. If this is the case, check the area before you water and only water if it is dry to the touch, at least until the soil is improved.
You will need to help improve the soil around them, and this can take some time. Adding lots of earthworms to the area will help (they will dig aeration through the soil as they go) and this article will help with improving your clay soil: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-to-improve-clay-soil.htm