Which flower is commonly used to add height in floral arrangements?

Delphinium is commonly used to add height in floral arrangements due to its tall, spiky structure and elongated blooms. This flower often grows in vertical spikes that can reach impressive heights, making it ideal for creating dimension and vertical lines within an arrangement. The height provided by delphiniums helps to draw the eye upwards and can complement shorter, more rounded flowers effectively, creating a balanced and visually appealing display.

In contrast, while roses and carnations are popular choices for floral arrangements, they typically have a more bush-like form, which is better suited for creating volume and fullness rather than height. Lilies, although they can also grow tall, do not have the same spiky structure as delphiniums, which makes them less effective for this specific purpose. Therefore, delphinium stands out as the best option for those looking to achieve height in floral designs.