Which of the following is NOT an important factor in planting design for bedding plants?

In planting design for bedding plants, the type of fertilizer is not a fundamental element of the visual and structural arrangement of the plants in a bed. Instead, the emphasis in planting design primarily revolves around aesthetics and functionality, which are shaped by color coordination, height arrangement, and plant spacing.

Color coordination plays a vital role in creating visual harmony among the plants and ensuring that the display is attractive. Height arrangement is important for layering and creating interest in the landscape, as taller plants can provide a backdrop while shorter ones create a foreground. Plant spacing is essential to ensure that each plant has enough room to grow without overcrowding, which can lead to issues with airflow, light penetration, and competition for nutrients.

While the type of fertilizer is crucial for ensuring plant health and promoting growth, it pertains more to plant care after installation rather than the initial design principles of planting. Therefore, in the context of designing a bedding plant layout, it is appropriate to conclude that the type of fertilizer does not factor into the physical and aesthetic considerations that define the layout and appearance of the planting design.