We, Oleanders (*Nerium oleander*), are elegant, evergreen shrubs known for our showy, fragrant flowers that bloom in shades of white, pink, red, and yellow. Hailing from the Mediterranean region, we are supremely adapted to warm, sunny climates. It is crucial for any gardener to understand that every part of our being—leaves, stems, flowers, and sap—contains potent cardiac glycosides, making us highly toxic if ingested by humans or animals. This is our primary defense mechanism against herbivores. Handle us with care, wearing gloves when pruning to avoid skin irritation from our sap.
We thrive in the warm climates of USDA hardiness zones 8 through 10. In these regions, we can grow as large, robust shrubs or small trees. For gardeners in zone 7, providing a thick layer of mulch over our root zone in winter can offer sufficient protection for survival. Our most fundamental need is abundant sunlight. We demand at least six hours of direct, unfiltered sun each day to perform adequate photosynthesis, which fuels our vigorous growth and prolific flowering. Planting us in partial or full shade will result in a leggy, sparse appearance with significantly reduced blooms.
We are remarkably adaptable regarding soil conditions, but we have clear preferences for optimal health. We perform best in well-draining, moderately fertile soil. While we are tolerant of a wide pH range, a neutral to slightly alkaline soil is ideal. The single greatest threat to our root system is standing water, which quickly leads to fatal root rot. When planting, ensure the hole is no deeper than the root ball but two to three times wider to encourage lateral root growth. If dealing with heavy clay soil, amend it generously with compost or sand to dramatically improve drainage.
Once established, we are exceptionally drought-tolerant, a trait inherited from our Mediterranean ancestors. For the first growing season, water us deeply once or twice a week to help our root system expand into the surrounding soil. After this establishment period, we typically require no supplemental watering unless experiencing a period of extreme drought. Overwatering is a far greater danger than underwatering. Feed us in early spring with a slow-release, balanced fertilizer (e.g., 10-10-10) to support a season of growth and flowering. Avoid high-nitrogen fertilizers later in the season, as they promote tender new growth that can be damaged by early frosts.
Pruning is essential for maintaining our shape, controlling our size, and encouraging bushier growth with more flowers. The best time to prune us is in late winter or early spring, just before new growth emerges. We flower on new wood, so pruning at this time stimulates the season's bloom production. Always use sharp, clean pruning shears and remove any dead, damaged, or crossing branches first. You can then shape the plant as desired, making cuts just above a leaf node. Wear protective gloves and clothing to avoid contact with our toxic sap. Deadheading spent flowers is not necessary but can promote a tidier appearance.
