As a photosynthetic organism, my primary purpose is to convert light energy into chemical energy to fuel growth and reproduction. Flowering is an extremely energy-intensive process. If I am planted in a location with too much shade, my leaves cannot produce enough carbohydrates (sugars) to support the development of the large, complex flower buds I am known for. I may appear healthy with green foliage because I can produce just enough energy for basic survival, but there will be no surplus for blooming. I require a minimum of 6 hours of direct, unfiltered sunlight per day. If surrounding trees have grown and now cast shade, or if I was initially planted in a suboptimal spot, this is likely the cause of my flowerlessness.
When I am moved or divided, my root system experiences significant trauma. My fine, feeder roots, which are responsible for water and nutrient uptake, are damaged. As a perennial, my instinct is to prioritize re-establishing this root system to ensure my long-term survival. This redirects all my energy and resources away from the aerial parts of my body, especially the reproductive structures (flowers). It is common for me to take two to three years to fully recover from being transplanted and begin blooming reliably again. This is not a sign of ill health, but rather a necessary period of re-establishment.
This is a critical factor specific to my species. The eyes (the pink or reddish buds on my roots from which new stems grow) must be positioned at a very precise depth in the soil. If I am planted too deeply, more than 2 inches (5 cm) below the soil surface, the energy stored in my roots has to travel too far to reach the sunlight. This severely weakens the stems and prevents the flower buds from receiving the strength they need to develop. Conversely, if I am planted too shallowly, my delicate eyes can be exposed to freezing temperatures in winter and drying winds in spring, causing them to desiccate and die. The ideal depth is no more than 1-2 inches below the soil surface in most climates.
The soil is my source of essential minerals. An imbalance here directly affects my physiological processes. The most common issue is an excess of nitrogen (N). High-nitrogen fertilizers promote rapid, lush vegetative growth of leaves and stems at the expense of flowering. It signals to me that conditions are perfect for growing bigger, so I delay reproduction. What I need for bud formation is a fertilizer higher in phosphorus (P), the nutrient that specifically supports root development and flowering. A fertilizer with a ratio like 5-10-5 is much more beneficial than a high-nitrogen lawn fertilizer. Additionally, the soil pH is important; I prefer a neutral to slightly alkaline soil for optimal nutrient uptake.
If I am a young plant grown from a division, I simply may not be mature enough to bloom. My body needs time to build up sufficient energy reserves in my roots. Furthermore, the flower buds I form in the fall for the following spring are surprisingly vulnerable. A late, hard frost after the buds have begun to swell in spring can kill them. Alternatively, a particularly harsh winter without adequate snow cover (which acts as an insulating blanket) can damage or kill the buds. You might see small, blackened buds that fail to develop. Botrytis blight, a fungal disease, can also cause buds to turn brown and mushy, especially in wet, cool spring weather.
