I have posted this in the "Trees & Shrubs" forum as well. Please forgive me if such duplication is against forum rules and regulations. I am really desperate for some help!

I have some five year old Fiji Metrosideros shrubs at home. Lately, two of the plants have started to die, with the leaves drying out from the bottom up. There has been no growth of new leaves. However the small red flowers that appear in Spring and Summer continue to appear on the top half of the plant.

I have tried everything from judicious watering to fertilising the dying plants, but to no avail.

I really want to save these plants, and if someone could point me in the right direction, it will be much, much appreciated!

Thank you for your time!