From our perspective, the primary driver for a reduction in flowering is the strategic reallocation of energy and resources. Flower production is an incredibly energetically expensive process. It requires vast amounts of sunlight, water, and nutrients to create each vibrant bloom. As the intense heat and long days of mid-summer set in, our survival instinct takes precedence over reproduction. We must divert energy away from creating new flowers and towards maintaining our core vegetative structures—stems, leaves, and roots. This shift ensures we can withstand environmental stressors and survive to potentially flower again when conditions improve. It is a calculated trade-off: fewer flowers now for greater overall health and longevity later.
Mid-summer brings prolonged periods of high temperatures that are physiologically challenging for us. Extreme heat can cause heat stress, damaging our cellular functions and increasing water loss through transpiration at a dangerous rate. When our roots and vascular systems struggle to keep up with the water demand from the leaves, we enter a state of mild stress. In this state, initiating and developing new flower buds becomes a lower priority than simply conserving water and preventing wilting. Furthermore, consistently high night temperatures can disrupt our internal hormonal balance, particularly gibberellin and cytokinin levels, which are crucial for promoting flower initiation and development.
While we are sun-loving plants, the quality and duration of light in mid-summer can sometimes work against us. In some regions, intense afternoon sun can actually be too harsh, leading to sunscald on leaves and flowers, which forces us to dedicate energy to repair rather than growth. Conversely, if we are planted in a location that becomes shaded as surrounding plants grow taller and fuller, we may not receive the minimum required hours of direct sunlight (typically 6+ hours). Without sufficient solar energy from photosynthesis, we simply lack the fundamental fuel required to power the flower-making process.
The soil we are planted in is our sole source of sustenance. A prolific spring flowering display depletes the soil of essential nutrients, particularly phosphorus and potassium, which are vital for bud formation and overall blooming. If these nutrients are not replenished through fertilization, we become deficient and cannot produce new flowers. Additionally, frequent watering throughout the summer can leach soluble nutrients deep into the soil, far beyond the reach of our root systems. We are effectively starving, and a starving plant cannot afford the luxury of reproduction.
It is also part of our natural life cycle to focus energy on different stages of growth. After the initial intense burst of flowering in spring and early summer, a lull can be a normal period of rest and recuperation. During this time, we may channel energy into strengthening our root system and foliage to support a potential second flush of blooms later in the season. For older plants, especially, some energy is directed towards the development of seed pods from spent flowers. If these old, wilting blooms (seed heads) are not removed, we will interpret our reproductive mission as accomplished and cease investing energy in producing new flowers.
