From our perspective as plants, our nutritional needs are dictated by our growth cycle and the energy required to produce our magnificent, showy blooms. We oleanders (Nerium oleander) are robust, evergreen shrubs adapted to warm climates. Our primary need is for a balanced supply of macronutrients. Nitrogen (N) is crucial for the vigorous production of our deep green, leathery foliage, which is the engine of our photosynthesis. Phosphorus (P) is essential for the development of our extensive root systems and, most importantly, for the initiation and strength of our prolific flower buds. Potassium (K) ensures our overall systemic health, regulating internal functions and improving our resilience against diseases and environmental stresses. A fertilizer with a balanced or slightly bloom-boosting ratio, such as 10-10-10 or 5-10-10, is ideal for meeting these core needs.
Our internal biological clock is finely tuned to the seasons, and fertilizing in sync with this rhythm yields the best results. The key period for application is during our active growth phase. As the daylight increases and the soil warms in early spring, we break from our winter slowdown and begin a surge of new vegetative growth. This is the perfect time for the first application of fertilizer, providing the necessary nutrients to support this initial push. A second application should follow in late spring or early summer, as we shift our energy towards preparing for and sustaining our long blooming period, which can last for months. It is critical to cease fertilization by late summer. Applying fertilizer too late in the season encourages tender new growth that will not have time to harden off before cooler temperatures arrive, making us vulnerable to cold damage.
While your intention to feed us is appreciated, improper application can cause more harm than good. First, we are notoriously drought-tolerant once established, and our roots are sensitive to overwatering and salt buildup. Therefore, always ensure the soil is moist before applying fertilizer to prevent root burn. Secondly, a common mistake is over-fertilization. An excess of nitrogen, in particular, will lead to an overabundance of lush, weak foliage at the expense of our beautiful flowers. It can also make us more susceptible to pests like aphids. Finally, we are toxic plants. While this does not affect how you fertilize us, it is a fundamental part of our being and a key defense mechanism. Always wear gloves when handling us or our soil, and wash your hands thoroughly afterward.
