Two young, thin branches and the weight of the leaves is pulling them down? Maybe the colourbond fence generated more heat and light than normal causing the tree to become a bit spindly. You could try cutting off the thinest branch (on the left) and staking and tieing the other as a leader. Be careful not to break the remaining branch when tieing it.

Hi Jane. Is there any chance you could post a photo of your damaged plant? It's difficult to diagnose your plant's problem without seeing the damage. Did you notice any tiny caterpillars on the leaves before they developed the mottled appearance? Generally speaking Eucalypts recover from caterpillar infestations so if caterpillars are the cause of the mottled appearance then I'd recommend leaving well enough alone, sitting back with your favorite coffee & waiting for the recovery. In fact, caterpillars are the favorite food of Australia's cuckoos so if your lucky to have sufficient natural habitat to attract a cuckoo or two then you'll have a real bonus in your garden. The less toxins we have in the environment the healthier we'll be so I recommend you keep the spray kit under lock & key. I doubt that the part shade location is a factor.

Pls try again, if there's a pic posted I'm not seeing it. Are they in the hot sun, drying out, thirsty? Why, how are they losing their leaves. What conditions are they in? Indoor, outdoor, A/Ced? Lena

your tree will do best with a 5-1-3 ratio feed but yours is good. Your tree is to small to hold fruit. If my tree of that size flowers I will break the fruit off so the tree puts energy into twig growth. My best guess is your need a bigger pot and more feed. The light over head looks good. My setup for growth below. get 16 hours of light.I pull air through the root base 2-7 times a week. 7 times weekly after watering down to 2 times weekly when the soil is dry just before the next watering. Tree is 37 inches tall and about 8 months old since the first leaves came out from the grafted bud. It has flowered and all the fruit has dropped because the tree can not supply the needed energy for the fruit. If the fruit had held on I would have removed it. I feed the tree full strength Miracle Gro 24-4-16 and add a little 28-0-4 to up the nitrogen get close to 32-8-12. I flush the soil every other feeding to get rid of excess of any thing that builds up like salt. The soil runs about 70F and the foliage about 80F. 6b Steve