As an Emerald Green Arborvitae, my primary goal is to maintain my dense, vibrant emerald-green foliage and a strong, resilient structure. I am not a heavy feeder like some flowering plants, but I do have specific nutritional requirements to thrive. The most crucial element for my well-being is nitrogen (N), as it is the fundamental building block for the chlorophyll that gives me my rich color and supports the vigorous production of new, soft needles. However, a balanced diet is key. I also need phosphorus (P) for healthy root development, especially in my youth, and potassium (K) for overall physiological functions, including water regulation and disease resistance. Micronutrients like magnesium and iron are also vital to prevent my foliage from turning yellow or brown.
From my perspective, a slow-release, granular fertilizer designed for evergreen trees and shrubs is the most beneficial choice. A formulation with an N-P-K ratio such as 18-6-12 or 14-7-7 provides the high nitrogen I crave while still supplying adequate phosphorus and potassium. The "slow-release" mechanism is critical. It feeds me a small, consistent amount of nutrients over several months, mimicking a natural soil environment. This prevents the shock of a rapid nutrient surge, which can cause excessive, weak growth that is susceptible to winter damage and pests. It also drastically reduces the risk of fertilizer burn to my sensitive root system, which lies relatively close to the soil surface. Organic options like well-composted manure or a bio-stimulant fertilizer are also excellent, as they improve soil structure and microbial life, creating a healthier ecosystem for my roots.
My feeding schedule is intrinsically linked to my growth cycles. I have two main periods of growth: a significant flush in spring and a smaller one in early fall. Therefore, the best time to fertilize me is in early spring, just as the ground thaws and before new growth begins, typically around late March to April. This application provides the energy I need for that first major burst of growth. A second, lighter feeding can be done in late fall, around October or November, after the growing season has ended but before the ground freezes. This late-season feeding is not for top growth; it is to strengthen my root system, storing energy that will help me push out strong, healthy growth the following spring.
How you apply the fertilizer is as important as what you apply. My feeder roots extend outwards, often to a distance equal to my height or even further, but they are concentrated near the drip line—the area directly below the outermost circumference of my branches. You should spread the fertilizer evenly starting a few inches from my trunk and extending at least a foot or two beyond the drip line. After applying the granules, water the area deeply. This action dissolves the fertilizer's coating, activating the slow-release process, and carries the nutrients down to my root zone. Please avoid fertilizing me during the heat of summer, as this can stress me, and never fertilize me late enough in the season that it stimulates tender new growth vulnerable to frost damage.
