Re: Orange and mandarin trees - no blossom/fruit Post by Martin Page » Tue Apr 21, 2009 7:29 am Quite the reverse ... sulfate of amonia is a pure nitrogen fertilizer and will only encourage green leaf growth at the expense of flower production. There is a leaf curly issue on a number of leaves on the orange also, but don't seem to have any insect in them. To compensate for that you can transfer pollen from the stamens to the pistils of another flower using a small brush. It may well be that you are going to have a very large tree before it produces any flowers 2.

If your tree had some oranges in the past and not now, but it has been growing normally, then likely you don't have enough pollinators, bees, in your garden. so this isn't an issue any more either. I sprayed all trees with neem oil and it killed all aphids and white fly very well. If you did, then it may well be it's not mature enough to flower yet Orange trees grown from seed usuually take 8+ years to flower. Repeat for all the flowers. Commercially grown orange trees are usually grown by grafting the tree onto a dwarfing, cold resistant rootstock.

Orange tree leaves are nice and green however have sooty mildew on them due to aphids.