Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
1/14/02
Contacts:
Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
Yard and Garden Column for the Week Beginning January 18, 2002
Create a Tropical Landscape with Cannas
By Richard Jauron
Extension Program Specialist
Horticulture
Iowa State University
Most of us have dreamt of living in a tropical paradise. These dreams usually occur while we're scraping frost from the car windshield or shoveling snow off the driveway. While most of us will never get the chance to live those dreams, gardeners can create a "tropical paradise" in Iowa. Indoors you can grow orchids, ferns, palms and other tropical plants. Outdoors cannas can create a tropical look in your summer garden.
Cannas are bold, exotic-looking plants grown for their attractive flowers and foliage. Flower colors include yellow, orange, pink and red. The large, banana-like foliage may be green, bronze or burgundy. The foliage of some varieties is striped or marbled in various colors. Most canna varieties grow to a height of 3 to 5 feet, but a few "giants" may reach 8 to 10 feet. Any of these varieties can be used as temporary screens, accents in beds or background plantings in borders. There are dwarf varieties that grow only 1 1/2 to 2 feet tall and do well in containers.
Cannas are usually grown from rhizomes. Rhizomes can be planted directly outdoors after the danger of frost is past (mid-May in central Iowa) or started indoors in large pots in March. Plant the rhizomes 4 to 5 inches deep.
Some varieties also may be grown from seeds. The most popular seed-grown cannas are from Tropical Series and include 'Tropical Rose' (All-America Selection in 1992), 'Tropical Red' and 'Tropical Salmon.' These usually grow 2 to 3 feet tall.
Seeds should be sown indoors in mid- to late-February in a commercial germination medium, such as Jiffy Mix or Redi-earth. Lightly cover the seeds and water. Maintain a temperature of 70 to 75 degrees F. Germination should occur in 7 to 14 days. When seedlings are large enough to handle, transplant them into individual pots. Plant them outdoors after the danger of frost is past. They should flower about 90 to 120 days after the seed was sown.
Cannas perform best in moist, well-drained soils in full sun. Water once a week during dry weather. To promote growth, fertilize once a month with a balanced garden fertilizer such as a 10-10-10. Remove spent flowers to promote additional blooming. While cannas have a few insect and disease pests, none are considered serious.
Here is a list of the most popular varieties.
'Aida' - soft pink flowers, dark green foliage, 3 to 3 1/2
feet
'Black Knight' - crimson red flowers, burgundy leaves, 3 to 3 1/2 feet
'City of Portland' - coral pink blossoms, green foliage, 3 1/2 to 4 feet
'Cleopatra' - yellow flowers with red spots, dark green foliage with bronze-red
markings, 3 to 4 feet
'Crimson Beauty' - rose-red flowers, green foliage, 3 to 4 feet
'Inferno' - orange/red flowers, green/yellow/orange/pink striped foliage,
3 to 4 feet
'Lucifer' - red flowers with yellow borders, green leaves, 2 feet
'Miss Oklahoma' - watermelon pink blossoms, green foliage, 3 feet
'Pretoria' ('Bengal Tiger') - orange flowers, yellow/green striped foliage,
4 t o 6 feet
'Red Futurity' - dark red flowers, burgundy foliage, 3 to 3 1/2 feet
'Richard Wallace' - golden yellow flowers, green leaves, 4 feet
'Rosamond Cole' - orange/red flowers with yellow edges, dark green foliage,
3 feet
'Striped Beauty' - yellow flowers with white markings, green foliage with
creamy yellow stripes, 3 feet
'Stuttgart' - orange flowers, green and white variegated foliage, 3 to
4 feet
'The President' - scarlet blossoms, green leaves, 3 to 3 1/2 feet
'Wyoming' - orange flowers, bronze/red foliage, 3 to 3 1/2 feet
In Iowa, cannas are tender perennials. Cut plants back to 6 to 8 inches above ground a few days after a hard, killing frost. Then carefully dig up the canna clumps with a spade or fork. Leave a small amount of soil around the rhizomes. Allow them to dry for several hours.
Store in large boxes, wire crates or mesh bags in a cool (40 to 50 degree F), dry location. Large clumps can be divided next spring before planting. Each section should have at least 3 to 5 buds.
If scientists are correct about global warming, Iowa may eventually become a tropical paradise. In the meantime, we'll have to be content with creating a "tropical landscape" with cannas, calla lilies, elephant's ear, angel's trumpet (Brugmansia) and other exotic plants.
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ml: isugarden
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