Yes, Osmocote Indoor and Outdoor has nitrogen and iron to green up all plants. Some conifers also need soil on the acid side in order to absorb the nitrogen that makes their needles green. Do you live in an area with naturally acid soil? This is usually an area with lots of rainfall. If you have other acid loving plants such as rhododendrons and azaleas also turning yellow you may want to do a soil test to see if your soil is acidic enough for these plants.  You can purchase an at home soil test to check the ph of your soil at garden centers and nurseries. To correct yellow plants in soil that is neutral or not acidic you should use Osmocote made for Rhododendrons, Azaleas and Camellias. Conifers and blueberries are other plants that benefit from the Osmocot for acid loving plants. Keep growing, Marianne Binetti