Grasp the gladiolus spike, or stalk, between the second and fourth leaves. Ideally, four leaves should remain on the portion of the stalk still attached to the plant, recommends the University of Missouri Extension. Select a stalk that has between one and three open blooms; the remaining buds will bloom after cutting.
Cut the gladiolus stalk diagonally with garden shears.
Place the gladiolus stalk in a tall vase filled with warm water. Keep the stalks in a vertical position until you use them in an arrangement.
Move the vase to a cool area that receives little to no light for two to three hours prior to placing the gladiolus stalk in an arrangement, recommends North Dakota State University Extension.