What causes the inability of water to enter the stem of flowers, leading to a common issue?

The issue referred to is commonly known as "bent neck," which occurs when a flower stem cannot adequately transport water to the bloom. This often happens because of a blockage in the stem's vascular system, usually caused by air bubbles that form during the flower's initial cut or due to bacteria growth. When the cut end is not submerged in water, air can enter the stem, creating a vacuum effect that prevents water from being absorbed. This results in the characteristic bending of the flower head and an inability to maintain proper hydration.

The phenomenon of bent neck highlights the importance of proper hydration techniques in floral arrangements. By ensuring that cuts are made underwater or by using appropriate preservatives, one can mitigate the risk of air blockage and help the flowers sustain their vitality over time.