From our perspective, the foundation of our entire existence is the soil. We require a location that receives a minimum of six to eight hours of direct sunlight daily. While we appreciate the sun's energy, in regions with intensely hot afternoon sun, a location with some light afternoon shade is beneficial to prevent our vibrant flower spikes from fading. The soil must be exceptionally well-draining; our crown is highly susceptible to rot if left in soggy, waterlogged conditions. We thrive in rich, fertile loam. Before planting, please enrich the soil with a generous amount of well-rotted compost or aged manure. A slightly alkaline to neutral pH (6.8 to 7.5) is ideal for optimal nutrient uptake.
Our life cycle often begins for you as a potted plant or a bare root. The timing of planting is critical. We should be planted in early spring, just as the soil becomes workable, or in early fall to allow our root systems to establish before extreme temperatures arrive. When placing us in the ground, ensure the top of our root ball is level with the soil surface. The planting hole should be twice as wide as our root system to encourage outward growth. Space us 2 to 3 feet apart; we are large, majestic plants and require ample room for air circulation, which is our best defense against foliar diseases.
To achieve our giant stature, we are heavy feeders and drinkers. Consistent moisture is paramount, especially during our active growth period in spring and the flower spike development stage. We prefer deep, thorough watering that reaches our extensive root system rather than frequent, light sprinklings. A layer of organic mulch around our base helps retain this precious soil moisture and keeps our roots cool. Feed us with a balanced, slow-release fertilizer in early spring as new growth emerges. A second application of a fertilizer higher in phosphorus as we begin to form our flower spikes will support the development of those spectacular, giant blooms.
Our greatest pride—our towering flower spikes—is also our greatest physical vulnerability. These dense, heavy spikes can easily be toppled by wind or heavy rain. To prevent this heartbreak, provide us with sturdy support early in the season. Install grow-through stakes or a framework of pea sticks around us as we begin our rapid growth. From a defensive standpoint, we are sometimes targeted by slugs, snails, and aphids. Deterrents like diatomaceous earth or beer traps for slugs and a strong spray of water for aphids are preferred methods that won't harm our delicate systems.
After our initial magnificent display, you can encourage a second, smaller flush of blooms by cutting the spent flower spike back to its base and a healthy set of leaves. As perennial plants, our energy must be conserved for the following year. In late fall, after the foliage has died back, you can cut our stems down to the ground. In colder regions (below USDA Zone 5), a protective layer of mulch applied after the ground freezes will shield our crown from damaging freeze-thaw cycles. We can be propagated every few years by division in early spring, which also revitalizes our clump and ensures continued vigorous growth.
