From our perspective, nitrogen is the engine of our growth. It is a fundamental component of chlorophyll, the molecule that allows us to capture sunlight and convert it into energy. When we are deficient in nitrogen, this entire process slows down. You will see it in our oldest leaves first, as we mobilize the remaining nitrogen to support new growth. They will turn a uniform pale green or yellow (chlorosis), and our overall growth will become stunted and weak. We simply cannot produce the lush, dark green foliage we are known for without it. To help us, a side-dressing of a balanced, slow-release organic fertilizer or blood meal in early spring as we break dormancy provides a steady supply of this crucial nutrient without the risk of a damaging rapid flush.
While you admire our flowers, we are relying on phosphorus to produce them. This nutrient is vital for energy transfer within our systems, supporting strong root development, flower formation, and overall metabolic processes. A phosphorus deficiency is particularly frustrating for us because we have the energy to grow but lack the key to unlock it for reproduction. You may notice our growth is stunted, our leaves might develop a purplish or reddish tint on the undersides or veins, and most disappointingly, we will produce very few, if any, of those beautiful blooms you planted us for. To correct this, we benefit greatly from the addition of bone meal or a fertilizer with a higher middle number (e.g., 5-10-5) worked gently into the soil around our base in early spring, giving our roots time to absorb it before our flowering cycle begins.
You might think of potassium as our immune and circulatory system. It is not a building block like nitrogen but a regulator that activates enzymes, controls water uptake within our cells, and improves our overall disease resistance and winter hardiness. Without adequate potassium, we become stressed and vulnerable. The signs are often subtle at first: the edges of our older leaves may appear scorched or burnt (necrosis), and we become more susceptible to fungal diseases and environmental stresses like drought. To fortify us, an application of potash or a balanced fertilizer containing potassium in the fall helps strengthen our cell walls and prepares us to withstand the winter cold, ensuring we emerge healthy and vigorous in the spring.
Our leaves should be a deep, true green. When they turn yellow while the veins remain distinctly green (interveinal chlorosis), it is a clear sign we are struggling to uptake iron. This is often not because iron is absent from the soil, but because the soil pH is too high (alkaline). In alkaline conditions, iron becomes chemically locked up and unavailable to our roots. From our root's perspective, the iron is there, but we cannot access it. This is a common issue for us in soils that have been heavily amended with lime. To fix this, applying chelated iron directly to the soil or as a foliar spray provides an immediately available form of the nutrient. For a long-term solution, amending the soil with elemental sulfur or organic matter like composted oak leaves can gradually lower the pH to a more suitable slightly acidic to neutral range where iron is naturally soluble.
