From the perspective of a newly planted oleander (Nerium oleander), the primary concern is root establishment. My root system has been severely disturbed during the transplanting process. In the nursery, my roots were confined to a pot, and now they are in a much larger volume of unfamiliar soil. Initially, my roots are not efficient at seeking out moisture on their own. I require consistent moisture in the immediate root ball area to encourage new root growth into the surrounding soil. However, my roots are also highly susceptible to rot if they are left sitting in saturated, oxygen-deprived mud. The goal is to provide me with enough water to thrive without suffocating me.
Immediately after planting, I need a deep and thorough watering. This initial soaking serves two vital purposes: it settles the soil around my root ball, eliminating large air pockets that could dry out my tender new roots, and it ensures the entire root mass is in contact with moist soil. For the first one to two weeks, my watering needs are very specific. I should be watered deeply every second or third day, depending on the weather. The key is to check the soil moisture before watering. Insert a finger about 2-3 inches into the soil near my base. If it feels dry at that depth, it is time to water. This frequent schedule hydrates me while my roots are still mostly within the original root ball.
After the initial two-week period, my roots will have begun to grow outward into the amended backfill soil. As my root system expands, I can begin to access a larger reservoir of moisture and nutrients. Consequently, the watering frequency can be gradually reduced. You should transition to a schedule of deep watering once a week. A deep watering means applying water slowly and for a long enough duration that it penetrates 8-12 inches into the soil. This practice encourages my roots to grow deeper and stronger, making me far more resilient to drought in the future. Always perform the finger test before watering to avoid over-saturation.
My water requirements are not dictated by the calendar alone. Several external factors greatly influence how quickly I use available soil moisture. Temperature and Sun Exposure: During hot, sunny, and windy weather, I will lose water through my leaves (transpiration) much more rapidly, requiring more frequent irrigation. Conversely, during cool, cloudy, or rainy periods, I will need far less supplemental water. Soil Type: The soil I am planted in is crucial. If I am in fast-draining sandy soil, water percolates away from my root zone quickly, meaning I may need water more often. If I am in heavy clay soil that retains moisture, the intervals between watering must be longer to prevent root rot. Mulching: A 2-3 inch layer of organic mulch around my base (keeping it away from the main stem) is immensely beneficial. It helps regulate soil temperature and drastically reduces moisture evaporation from the soil surface, meaning the water you provide lasts longer for my roots.
