The greatest visual impact in a landscape is obtained when bedding plants are arranged in what way?

The greatest visual impact in a landscape is achieved by arranging bedding plants in masses together. This technique involves grouping a significant number of the same kind of plant or color in a way that creates a bold statement. When plants are placed in substantial clusters, it enhances their visual strength and allows for a striking display of color and texture that draws attention. This massing effect can lead to dynamic visuals, creating a cohesive look and making a plant's unique features stand out in the landscape.

In contrast, separating plants by color can cause a fragmented appearance and may not allow any single color to make a strong impact. Arranging plants in a single row could create a linear layout that lacks depth and visual interest, preventing the design from having a more engaging three-dimensional effect. Alternating heights, while it can create architectural interest, may not provide the same immediate visual impact as massing does, as it can lead to more subtle variations that don't capture attention as effectively. Thus, massing together is the most powerful technique for achieving a strong visual effect in landscaping.