I have a 2 newly planted from pot Lilly pilly sublime trees that are not doing well. One in particular is very dried out with dull leaves that are dry and falling and some burnt tips. I have watered in, applied seasol to roots and on top and general fertiliser when planting. It gets full sun a few hours a day and partial sun rest of day. I have another 5 plants planted at same time doing great so not sure about these two. Could nearby gum tree or teddy bear magnolia be sucking soil nutrients? Please advise I do not want to overwater and drown roots as I’ve read it is a hardy drought resistant plant.
If the plant is being watered and the leaves are drying out, the problem is most likely related to the roots.
There are various things it could be:
# poorly drained soil in that spot causing the roots to rot,
# curl grubs or other insects eating the roots
# roots damaged at the time of transplantation.
# Pot bound, kinked and girdled roots because of poor propagation techniques at the nursery
If it is the later, your only choice will be to remove and replace as it is likely the plant will never be fully healthy.
Firstly, I would be lightly pruning the plant to remove all the dead stems and leaves, feeding it and seeing if it recovers.
If not you may need to dig the plant up to exam the underground parts of the plant, you can then check how the soil is draining, look for curl grubs and examine the roots to see if they are healthy with a main roots growing downwards and lateral roots growing outward from it. If the main root is kinked or girdling the plant may fail to thrive.