Cannas

Cannas- Bold and Beautiful

If you crave bold accents and lush tropical foliage in your northern garden then cannas are the plants for you.  These bold beauties have made a big come back and canna rhizomes of choice varieties regularly sell out in stores and catalogs.  Cannas are easy to grow, relatively inexpensive, and dramatic additions to tired old flowerbeds.  With a huge selection of flower and leaf colors, there is sure to be a canna that will add pizzazz to your garden.

Tall cannas are accent plants in garden borders, the center of island beds or back of other beds. There are cannas for large spaces and tiny cannas just right for containers.  While the flowers of some varieties of cannas are the show, in others it’s the huge, tropical appearing foliage.  The foliage is often more dramatic than the flowers.  Some new varieties have wonderful foliage and  beautiful flowers.

Tall cannas can also be used as a screen, or flowering hedge.   Smaller cannas can be used anywhere in beds to give late summer color, for foliage color and texture, and are excellent for containers.  Cannas can also be used as accent plants in water or bog gardens.

Canna culture

Cannas will grow almost anywhere, below zone 7 they are a summer flowering plant whose rhizomes can be easily lifted and stored in the winter.  Occasionally in a sheltered spot cannas will even over winter in the ground.  And cannas are indeed tropical plants, flourishing in heat and humidity.

Canna leaves are usually large and broad, with a heavy rib down the center.  They can be various shades of green, burgundy and red often with splashes of white or yellow or stripes of color following the leaf veins.   Depending on variety, cannas grow from 16 inches to 10 foot in height.   The rhizomes increase horizontally underground, throwing up new shoots until the plant becomes a huge clump.

The flowers of cannas come near the end of summer, on long stalks at the top of the plant.  They are often described as orchid like- or gladiolus like.  They can be large and striking in modern varieties but may be smaller and less glamorous in some older cannas.  Canna flowers come in all colors and color combinations except blue, purple or true white.  Canna seed is a hard, round, black ball which gives cannas the common name of Indian Shot.

Cannas are usually purchased as bare rhizomes in the north, or as potted plants.  Look for rhizomes that are large and firm with two or more buds on them.  Start rhizomes indoors about 6 weeks before your last frost in pots of good, rich potting soil.  The pots should be in a warm, sunny area and kept well-watered.   The rhizomes may also be planted directly in the ground after the last frost when the ground is warm, but they may be slow to start growth and late to bloom.  

Cannas may survive zone 5 winters in a protected area, although they are so slow to start growing in the spring that they seldom have time to bloom before fall.  It is better to dig up the rhizomes and store them over winter. 

Cannas give a lot to the garden but they are greedy guests needing lots of sun, lots of moisture, lots of heat, lots of fertilizer and organic matter.  Rich, moist soil in full sunlight is ideal for cannas.  Cannas will even do well in pots sitting in water if there is some soil above the water line.  Fertilize cannas once a month with a fertilizer formulated for flowers and water frequently for spectacular results.

In zones 6 and lower, when a frost has killed the canna foliage, carefully dig up the rhizomes.  You will probably find a few more than you planted.  Shake off the dirt and allow the rhizomes to dry in the sun a few days.  Don’t allow them to get frosted or frozen while drying.  Then store the rhizomes in a cool, but frost-free place in sand, peat or vermiculite.   Before planting you can divide large rhizomes as long as each piece has at least one bud, preferably two, to a section.  You can trade or give away the excess if you have more than you care to plant.

Some varieties

There are so many wonderful cannas on the market now that you will be tempted to become a collector.  Small canna varieties include, ‘Dwarf Wyoming’- gold flowers and dark maroon veined foliage, ‘Pink Surprise’- hot pink flowers edged with yellow, green foliage, ‘Bankok’- bright yellow flowers and green foliage striped with white, and ‘Lucifer’-one of the smallest, scarlet red flowers touched with gold and green foliage. 

Large canna plants include; ‘Australia’- almost black foliage and hot red flowers, ‘Tropical Sunrise‘- a blend of peach, pink and yellow flowers with green foliage, ‘Cleopatra’- an always changing mosaic of red and yellow flowers and green leaves marked with purple in various patterns, ‘Constitution’ has narrower leaves than other cannas in an odd gray- purple shade and pastel pink flowers, “Ermine’ has very pale, almost white flowers. green leaves, ‘Tropicana’- leaves boldly striped in yellow and red on a purple background and screaming orange flowers, ‘Stuttgart’- lovely green foliage variegated with white, peach colored flowers, and the classic ‘King Humbert’- golden yellow flowers with red spots and green leaves. 

Canna Ehemani has drooping flowers

Some extreme cannas grown for their foliage are ‘Musafolia’- up to 10 foot high with huge broad leaves that are green edged with red, and ‘Intrique’- a canna with unusual narrow, gray green leaves that grows up to 7 foot tall.