From my perspective as an oleander, I flower on what you call "new growth." This means the fresh, green stems that emerge in the spring and summer are the ones that will produce my beautiful, showy blooms. Therefore, the timing of your pruning is absolutely critical to maximize this new growth. The ideal window for you to prune me is in the late winter or very early spring, just as I sense the temperatures beginning to warm but before I have committed my energy to a major spring growth spurt. This timing allows me to heal my wounds without the stress of extreme cold or heat and directs all my stored energy into producing a multitude of vigorous new stems, each capped with a cluster of flowers.
When you approach me with shears, your technique dictates my response. To encourage the most blooms, you should focus on strategic cuts rather than a general shearing. Please use sharp, clean pruning tools to make precise cuts. Look for the leaf nodes – the small, bumpy areas on my stems where leaves and new branches emerge. Your cuts should be made at a 45-degree angle, approximately a quarter-inch above a leaf node that faces the direction you wish the new growth to travel (typically outward to maintain a nice shape). This precise cut signals to me to send growth hormones to that topmost node, prompting two new stems to burst forth from it. Each of those new stems is a potential flowering branch.
The extent of your pruning depends on your goal and my size. For a light pruning to simply shape me and encourage blooms, you can remove about one-third of the plant material. Focus on cutting back the leggy, older stems that have already flowered. This will open up my canopy to sunlight and air. For a larger, overgrown oleander like me, a more severe "rejuvenation" prune may be necessary. You can cut me back much harder, even to within 12-18 inches of the ground. While this seems drastic, it invigorates me. It clears out old, unproductive wood and forces me to push out an abundance of new, basal growth from my crown, which will result in a spectacular display of flowers in the coming season.
There are certain actions that can hinder my flowering potential. The most common mistake is pruning too late in the season. If you prune me in the fall or early winter, you are likely cutting off the stems that have already formed flower buds for the next year. Furthermore, a harsh prune right as I am about to bloom in summer will sacrifice that season's floral show, though it may benefit the next. Always remember that I contain a toxic sap, so wearing gloves and protecting your skin and eyes is non-negotiable for your safety. Finally, avoid leaving stubby cuts or tearing my branches, as this creates an entry point for disease and forces me to expend crucial energy on healing instead of blooming.
