Funding a daring, tropical appearance to the yard, cannas (Canna x generalis) top broad leaves with sturdy blossom stalks bearing colorful, sometimes almost orchidlike blooms. Garden cannas are the result of hybridizing about nine wild species of cannas with each other, then crossing those hybrids with one another. They develop in U.S. Department of Agriculture plant hardiness zones 8 through 12. Countless varieties exist, with a wide assortment of plant heights, leaf colors, blossom shapes and flower colors. Use these features to help identify the type of canna.
Plant Size
The extent of a mature canna plant helps identify it again. Four major categories of cultivars group cannas with their height. Pixie cannas grow from 1 1/2 to 2 feet tall. Dwarf cannas reach heights between 2 and 3 feet. Medium cannas vary from 3 feet to 5 feet tall, and tall cannas grow from 5 to 6 1/2 feet tall. When you know what height category to look under, use additional features, such as leaf and blossom shade, to further identify the plant.
Dark-Colored Foliage
Many canna cultivars have green leaves, but a few varieties have leaves tinged with darker colors, such as bronze or purple, especially in the fresh leaf. The older leaves generally revert back to a shade of green. An old favourite that originated in 1902, “King Humbert” contains dark, bronze-purple foliage and reddish flowers. Dark maroon leaves and red blooms look on “Black Knight.” Narrow, purple-bronze leaves and deep gold blooms identify “Semaphore,” dating from 1895. “Shenandoah” bears deep pink blossoms over burgundy leaves. Pink blossoms top 3-foot-tall reddish-black foliage of “Zulu Pink.”
Patterned Foliage
Several cannas have variegated leaves marked in green, yellow or white. An older range from 1923, yellow-flowered “Bangkok” has green leaves with thin white stripes. “Bengal Tiger,” also known as “Pretoria,” bears yellow- and green-striped leaves with wide-petaled, yellow and orange blooms. The real rainbow colors come in newer varieties such as “Tropicanna,” with orange blossoms against leaves striped with burgundy, gold, yellow, green and pink. Not quite as colorful but still stunning, “Pink Sunburst” leaves have wide, reddish-pink strips contrary to dark green.
Flower Color and Shape
Canna identification depends heavily on flower color and shape. The most frequent canna flower colors are yellow, orange and red, although the flowers may be any color except for blue, black or green. Some blooms have two different principal colors, or are rimmed or edged with another colour. Others have blotches or speckles on the petals. Flower shapes are of two primary types. Canna flowers with wide petals that are closely spaced on flower stems are called gladiolus-type flowers. Cannas with thin petals spaced more broadly about the flower stalk are termed orchid-flowering cannas.