Canna flowers are very large plants with vibrant blossoms on stalks that can easily grow 4-6 feet tall. The floral displays are striking in bright colors including pink, yellow, orange and red. The canna plant is grown from rhizomes so it is not necessary to let the blossoms wilt and go to seed. You can have weeks of additional blooming time if you "deadhead" or remove the wilted and dying blossoms from the plant. The complete removal of wilted petals and the seed producing ovary will give the plant a chance to produce more canna flowers.
Look at your canna plants and observe the wilted and dying blossoms at the top of the various stalks. Locate where the new bud growth is on the stalk to determine what areas of the stalk should be saved.
Grasp a canna stalk in one hand and slightly pull it forward so that you can keep a good grip on it.
Cut only the dead blossoms away with a sharp knife at the exact point where the flowers have grown out of the stalk, just under the calyx, if there are healthy new buds on it. The dying blossoms sap energy and nutrition needed for new growth and new canna flowers.
Place your knife or garden shears just under the mature or dying canna blossoms near the bottom or base of the entire stalk if there is no sign of new bud growth on it. A pair of sharp garden shears is also a good tool for cutting through the thick stalks without bruising the remaining plant stalks.
Cut straight through the stalk away from you until the stalk drops off of the plant.