Question: I have several kinds of spiraeas, but they never get very dark green. I’ve tried my standard lawn fertilizer, but it hasn’t helped. What do they need?
Answer: Probably iron. The variety Anthony Waterer commonly shows iron deficiency in the western two-thirds of Texas, most especially when we try to grow it in shallow chalky soils. Whenever possible, plant them in a rich, organic soil. As needed, apply iron and sulfur to correct the chlorosis.