Are there any Mulberry bushes that have bright yellow leaves in the summer if in the sun? There is a bush where I live that has brilliant yellow leaves on top of the bush but underneath growth is green. I was told it was a Japanese Mulberry. I haven't found any info to verify that. The bush is large about 8 feet.
Japanese mulberry is Morus australis - new leaves are not yellow, but the leaves do turn yellow as the weather cools and goes into Fall/autumn, see here for info and images http://www.cirrusimage.com/tree_Japanese_mulberry.htm.
Depending where you live, if overnight temperatures have fallen recently, or the weather has been very dry this summer as well as turning cooler, that might explain yellow leaves at the top. Otherwise, please add photographs of the whole plant and a close up of the foliage to your question for correct ID.