This has been planted with several others that all seem to be thriving, this one seems to be dying back. All planted mid April 2021. It seems to be dying back, leaves changing colour. please can you let me know of possible reasons as we do not want to loose the others.
This resembles the conditions and looks of Verticillium Wilt. Controlling this, immediately, will be necessary. This article well help:
https://www.gardeningknowhow.com/plant-problems/disease/verticillium-wilt-treatment.htm
Here is an article that will help you with the care of the shrub:
https://www.gardeningknowhow.com/ornamental/shrubs/elaeagnus/how-to-grow-elaeagnus-limelight.htm
I have 10 elaeagnus compacta that were planted last June. Through last summer and into autumn they have appeared healthy with some new growth appearing. Over the last couple of weeks the new growth that has come through has small yellow leaves. The older leaves still appear to be green and healthy. I have looked for pests but see none.
That looks like spider mite damage! They are very tiny, and you may not see them without a magnifying glass. Under my microscope, they look quite terrifying. And they can be.
These tiny terrors are a problem in my indoor and outdoor plants. You will need to treat vigorously and every few days to keep them at bay. Neem oil, or its active extract of azadirachtin, will be your primary defense. If that doesn't work, then your next option will be predatory insects. Ladybugs work well, but it is no guarantee that they will stay around being outside.
https://www.gardeningknowhow.com/plant-problems/pests/insects/spider-mite-treatment.htm