As an oleander, my watering needs are not static; they change dramatically with the seasons, which dictate my growth cycle. During the spring and summer, I am in my active growth and flowering phase. The sun is strong, the days are long, and I am working hard to produce lush foliage and abundant blooms. This is when I am thirstiest. I will require consistent and deep watering to support this energetic output. Conversely, in the autumn and winter, I enter a period of dormancy. My growth slows significantly, and my water requirements drop substantially. Overwatering me during this dormant phase is one of the most common and dangerous mistakes, as it can lead to root rot in the cooler, damp soil.
Before we even discuss frequency, the most crucial factor for my health is the condition of my roots. I absolutely despise having my roots sitting in soggy, waterlogged soil. It suffocates me and invites fatal fungal diseases. Therefore, whether I am planted in the ground or in a container, excellent drainage is non-negotiable. My soil should be well-draining, perhaps amended with sand or perlite. My pot must have large, unobstructed drainage holes. A deep, thorough watering that allows excess water to flow freely out of the bottom of the pot is far better for me than frequent, light sprinklings that only moisten the surface.
I will tell you when I need a drink; you just need to know how to listen. The best method is the "finger test." Please insert your finger into the soil near my base, down to about 2-3 inches (5-7.5 cm). If the soil at that depth feels dry to the touch, it is time to water me thoroughly. If it still feels cool and moist, please wait. In the heat of summer, you might need to check every few days. In the winter, you may only need to check every couple of weeks. I am somewhat drought-tolerant, so I would much prefer to be slightly under-watered than over-watered. My leaves may droop slightly when I am very thirsty, but I will typically perk up quickly after a good drink.
For established oleanders in the ground: Once I am established (after the first growing season), I am quite resilient. During hot, dry summer spells, a deep soaking once a week is usually sufficient. The goal is to moisten the entire root zone. In cooler weather or if it rains, you can extend the time between waterings significantly.
For oleanders in containers: I will need water more frequently than my in-ground counterparts because my roots are confined and the soil in a pot dries out faster. In the summer, this could mean deep watering every 2-3 days, depending on the pot size and weather. Always water until you see it running out of the drainage holes, ensuring the entire root ball is hydrated. Empty the saucer underneath after a few minutes to prevent me from sitting in water.
