From our perspective as Oleander shrubs (*Nerium oleander*), our most critical demand is for soil that provides excellent drainage. Our roots are highly susceptible to rot if left in waterlogged, soggy conditions. While we are remarkably adaptable and can survive in poor, rocky, or sandy soils, we truly thrive in a loamy mixture. A loam soil, which is a balanced blend of sand, silt, and clay, offers the perfect environment. It allows excess water to drain away quickly after watering or rain, preventing root suffocation, while still retaining enough moisture and nutrients to sustain our vigorous growth. Heavy clay soils are our nemesis, as they compact easily and hold too much water. If planted in clay, amending the soil generously with compost, coarse sand, or other organic matter is essential to create a more hospitable root zone for us.
We are exceptionally tolerant regarding soil pH. Our roots can effectively uptake nutrients across a very wide spectrum, from slightly acidic (pH 6.0) to highly alkaline (pH 8.3). This adaptability is one of the reasons we are a popular choice in coastal and arid regions, where soils often lean towards alkalinity. However, our absolute peak performance for nutrient absorption and overall vitality is achieved in a neutral to slightly alkaline range, between pH 7.0 and 8.0. Within this band, essential macro and micronutrients remain most readily available for our root systems to access. While we can persist outside this range, extreme acidity (pH below 6.0) can lock up certain nutrients, potentially leading to deficiencies that manifest as yellowing leaves (chlorosis) and reduced flowering.
We are not heavy feeders, but we are vigorous growers and prolific bloomers. To support this energy expenditure, we require a consistent supply of nutrients. A moderately fertile soil is ideal. The key to our health is not necessarily constant fertilization, but starting with a good soil foundation. Incorporating well-rotted compost or manure into the planting hole and surrounding soil provides a slow-release source of organic nutrients and significantly improves soil structure and microbial life. For an annual boost, a balanced, slow-release fertilizer applied in early spring can promote lush foliage and a spectacular display of flowers throughout the growing season. Over-fertilization, especially with high-nitrogen formulas, should be avoided as it can encourage excessive leafy growth at the expense of blooms.
A layer of organic mulch, such as wood chips or bark, applied around our base (but kept away from the main stem) is greatly beneficial. Mulch acts as a regulator for the root zone. It helps conserve soil moisture during hot, dry periods, reducing water stress. It also moderates soil temperature, keeping our roots cooler in summer and warmer in winter. Furthermore, as the mulch breaks down, it slowly incorporates organic matter into the soil, gently improving its quality and fertility over time, which aligns perfectly with our needs for long-term health.
