Hi, 

It is best to get your soil tested before applying any fertilizers. If the soil is sufficient in organic matter, and the pH (acidity) level is appropriate for the plants, they may not need any fertilizer. Typically if you are using an organic mulch, as it decomposes, it is adding nutrients back into the soil. Also if the plants are near a turf grass area and you are using any fertilizer or nutrients for your lawn, the shrubs are most likely getting enough as it moves through the soil.

The green growth could just be the new growth color which tends to darken as it ages and hardens off. If you would like to send us in some photos of the plants - the sun ones with new growth and the ones in more shade, we can try to assess what care they may need. If you can take a clear photo of the leaves up close that could help as well. 

Emily