Spiraea japonica is in flower here also. If you want to keep the part with the yellow leaves cut off the green-leaved branches.

Part of that is lighting ... it's not quite so distinctively two tone.

Here's a closer picture of its flower, also.

the size mentioned more closely describes 'goldmound'. in my area, it looks now like the one in your photo. 'goldmound' leafs out in spring with new growth of yellowish green and ages to a darker green. you will be able to tell next spring if it is 'magic carpet' if the new growth is red. both of these cultivars have the pink flowers, as do several other of these spiraeas with chartreuse colored foliage. many of them do stay in that size range but can always be pruned for size and shape.