Cannas, Cannas, Cannas - Canna Lilies for Your Garden

Canna 'Bengal Tiger'

by By Dennis Carey/Tony Avent
Plant Delights Nursery Inc.
9241 Sauls Road
Raleigh, NC 27603
919.772.4794

Introduction

Cannas are bold, tropical-looking, herbaceous perennial plants that bloom over a long period in summer and are cold hardy in much of the southern United States into USDA Hardiness Zone 7b. Cannas have been in and out of fashion during their long history, and are currently rebounding in popularity from a post WWII low. Currently, cannas are very popular everywhere in the United States. In the South, we plant-em and forget-em, but north of Zone 7b, they are easy to lift and store during the winter. We urge our readers to visit our garden during the summer and fall open house days to see our collection. You can also check out our web site to view our offerings.

Cannas should be located where they will have a visual impact at the height of summer. Most cannas are tall and need to be placed at the back of a bed, but there are some dwarf varieties that will look good at the front of the border. Here at our garden nursery, we combine cannas with spring bulbs, baptisia, daylilies, coneflowers, cuphea, and ornamental grasses. Cannas are 55mph plants and can be located along highways where they can be appreciated by drivers. In 1986, in preparation for the US Olympic Festival in Raleigh, we introduced the NC Department of Transportation Roadside Beautification Division to Canna Lilies, by sharing several dump truck loads of Canna 'The President' rhizomes from plantings that we had growing at the NC State Fair grounds. To say they liked cannas would be the understatement of the decade as visitors can now find canna lilies planted along highways from one end of North Carolina to the other.

History and Background of Cannas

Canna species are native to semi-tropical and tropical parts of North and South America. Their native range extends from South Carolina (Canna flaccida) south to Argentina and includes the Caribbean islands. In their native habitat, cannas live in damp shady locations along the margins of rivers and lakes.

Cannas are valuable as a food source in certain cultures because their rhizomes contain a high quality starch. The primary species used for food production is Canna indica. The starch (commonly called achira) is used in Vietnam to make high quality "cellophane" noodles. In the modern era of agriculture, canna is only rarely used as a primary food source, as it has been replaced by more nutritious and higher yielding crops such as potatoes and corn. Cannas have been cultivated as a food crop for over 4000 years in their native range in Central and South America.

In addition to food, cannas have a variety of other uses. Canna seeds are pea-sized, round, brown or black in color, and exceptionally hard. They have been used as shotgun pellets in India (hence the common name "Indian Shot"). The seeds are used as beads in jewelry, rosaries and have been incorporated into baby rattles and musical instruments. A purple dye can be extracted from the seed, and fibers extracted from the stem of the plant are used to make jute and paper. Cannas have been used for phytoremdiation (the use of plants to absorb toxins from soils), in order to remove toxic heavy metals such as copper and zinc from pig waste, and to remove excess fertilizer and insecticides from greenhouse runoff. In Thailand, cannas are a traditional father's day gift.

Although used for thousands of years as a food crop, cannas were not well-known to European botanists until the 1500s. They are first mentioned in the book The Vienna Codex (1536-1566). Cannas may have arrived in Europe from the Americas as early as Columbus's 1492 travels. By 1576, cannas were cultivated in gardens in several European countries; although, they only became widely popular as ornamental plants in the Victorian era (mid to late 1800s). Cannas had a particularly large following in France, Hungary, England, Italy, Germany, America and India during the late 1800s. Hundreds of cultivars with shorter habits and novel flower forms and colors were created between 1860 and 1910. Unfortunately, most of these cultivars were lost because European gardeners stopped growing cannas during the upheaval from World War I through World War II. In addition, garden fashions changed. In the first half of the 20th century prominent garden designers, such as Gertrude Jekyll, replaced formal looking Victorian gardens with informal, relaxed perennial borders. This led gardeners to largely abandon the plants used by the previous generation, including the canna. However, starting in the 1950s, cannas have been making a slow comeback in gardens, and today they are approaching their Victorian era popularity. Modern breeders have been releasing some wonderful cultivars and currently there are more than 2000 cultivars to choose from ... surely you can find at least one that you like.

Canna Morphology

Cannas are herbaceous perennials with a rhizomatous rootstock that allows them to spread slowly outward from where they are planted. Each individual stem consists of a central stalk with 10 to 12 leaves arranged alternately or spirally along it. Each plant may be 2' to 3' wide. In nature, the plants tend to be quite tall (7' to 16') but many shorter selections have been created for gardens. Once the plant has 6 to 9 leaves, it forms an inflorescence at the tip. After the inflorescence has finished flowering, that stalk begins to die and is replaced by a new stalk emerging toward the tip of the rhizome.

The rhizome is a thickened underground horizontal stem that sits just below the soil surface. As it elongates, it produces shoots that grow upward to produce leaves and flowers and fibrous roots at each node. The thickness of the canna rhizome varies by species. The cultivars grown for food have very thick rhizomes, but some species (especially the water-loving species) have thin or wiry rhizomes. In some species, the rhizome grows up to 24" (60cm) long and has many branches. Eventually the older parts of the rhizome die off naturally.

Canna leaves are usually large, banana-like, tropical-looking and bold. Most cultivars have rich emerald-green leaves, but some have purple/red or variegated leaves. The purple or red leaf color is usually quite dark and may cover the entire leaf, just the outside margin, or occasionally just the midrib. Variegation in cannas has two forms. It may consist of white or red splotches/sectors on green leaves (Canna 'Stuttgart'). Or, it may consist of narrow stripes of color between the minor veins (Canna 'Phasion' or Canna 'Bengal Tiger').

When canna leaves first emerge, they are rolled up and unfurl over the course of a day or two (unfurling occurs only at night). The leaves are generally waxy (glaucous) and may have a dull or shiny finish depending on the type of wax. The Water canna cultivar group generally has very narrow leaves compared to most others. The leaves have rounded sides that taper to a point at the tip (acute or short acuminate). The leaf blade tapers gradually into a sheath that merges with the stem and thus there is no leaf petiole.

The canna flower is very exotic. Technically, the 'flowers' are inflorescences, meaning that they are clusters of flowers on a single structure. A single terminal inflorescence forms at the tip of the stalk. The inflorescence may be straight and narrow (a spike) or quite well branched (a panicle or thyrse). The well-branched trait is strongly selected for by breeders as it is showier. Some canna florets open in the morning and look best during the daytime, while others are night bloomers whose beauty is waning by the next morning. Canna flowers are pollinated by a variety of organisms. Day-flowering cannas are pollinated by bees or hummingbirds and night-flowering cannas are pollinated by moths or bats.

Canna florets tend to be short-lived, lasting only a day or two. New florets open constantly and provide a continual bloom during the season. In temperate gardens, canna flowering usually begins in midsummer and will last until frost. The start date and duration of flowering varies by cultivar. Flowering is more prolific if gardeners remove the old flowers, taking care not to damage the unopened buds still remaining in the flower spike. In a greenhouse, cannas will generally not flower in the winter due to low light levels, and flowering may be curtailed during extremely hot temperatures.

Canna flowers range in color from pale-yellow, to orange, to blood-red, and all shades in between (salmon, apricot, and pink). Many people think that canna flowers only come in rich, saturated exciting colors like bright-red or yellow. However, there are many pastel shades of pink, primrose yellow, and pale orange. A few cultivars are marketed as being white, but that is not strictly true. The "white" cannas usually emerge a very pale yellow and mature to a cream color. There are no true white cannas in cultivation. Some of the Victorian era cannas were said to have been pure white, but they have been lost to history and we have no way of verifying these claims. There are no blue or purple canna flowers.

Canna flowers may be striped, streaked, spotted or splotched with contrasting colors. The most common form is a yellow or orange flower with darker red to brown splotches on it. There are a few picotee cannas that are red with a yellow edge. Occasionally the throat of the flower (where the staminodes overlap) will have a contrasting color. The labellum may have contrasting spots or stripes on it too.

This thick seed coat allows canna seed to survive for a very long time. In 1969, Canna indica seed was found in a 550-year-old archaeological dig in Argentina and was successfully germinated. The reason that the seed coat may be so thick is that fire plays a part in canna seed germination in its native habitat. In the wild, canna seed germinates best in places burned by fire, which not only weakens the seed coat, but destroys any competition for the emerging canna seedling.

Canna Taxonomy

The genus name canna comes from the Greek "kanna" and the Celtic "cana" which refers to "a reed-like plant" and is also the root of the musical term "canon". The name canna was applied to this genus as early as 1576 and was formally given to the genus by Linnaeus in his seminal work Species Plantarum. (Trivia: canna is the first genus described in Species Plantarum). Cannas are the only genus in the family Cannaceae. Cannaceae is in the order Zingibales and is thus distantly related to Banana (Musa), Bird-of-Paradise (Strelitzia), Heliconia, Maranta, and Ginger (Zingiber). Like these, canna is a monocot.

The taxonomy of the genus canna has been tumultuous and confused due to its worldwide cultivation for food and its extensive hybridization for ornamental use. In the past, experts have argued that there may be 50 to 100 species in the genus and used floral morphology to identify different species. However, modern taxonomists have declared many of these species to be either duplicates or to be cultivated hybrids that do not deserve a specific epithet. The prominent Japanese botanist Nobuyuki Tanaka wrote a monograph of the of the family Cannaceae in 2001 and indicated that there were 19 species in the genus. In 2008, H. Maas-van de Kamer and P.J.M. Maas released another canna monograph declaring that there are only 10 wild species in the genus. Maas lumped many of Tanaka's Asian canna species together under Canna indica using the argument that cannas are native to the Americas and any Asian taxa are merely descendants of Canna indica that spread worldwide as a food crop. Tanaka on the other hand has done cytological and genetic analysis of all the taxa and makes a case for 19 genetically distinct cannas based on morphology, DNA analysis, and pollen structure. Plant taxonomists often have disagreements of this sort. Different breeders and growers may choose to follow one taxonomist or the other as their preferred source. Kew gardens in England has sided with Tanaka for the time being, and has assigned all of the historical species to one of Tanaka's 19 species.

The ten wild species according to Maas are:

1. Canna bangii
2. Canna flaccida - used as a source of yellow flowers and scent in modern cultivars.
3. Canna glauca - used extensively in modern cultivars for its form and tolerance of wet feet.
4. Canna indica - parent of agricultural cannas. Used extensively in modern cultivars for its form, branched inflorescences and early flowering.
5. Canna iridiflora - used extensively in modern cultivars for large flowers, long bloom period, self-cleaning flowers, and cold tolerance.
6. Canna jaegeriana
7. Canna liliiflora - used extensively in modern cultivars for large flowers, off-white flower color, and flower scent. It has poor cold tolerance and is difficult to grow.
8. Canna paniculata
9. Canna pedunculata
10. Canna tuerckheimii

    The nine additional species according to Tanaka are:

11. Canna amabilis
12. Canna coccinea
13. Canna compacta
14. Canna discolor - Maas considers this to be Canna indica. This is the main agricultural species.
15. Canna jacobiniflora
16. Canna patens - Maas considers this to be Canna indica.
17. Canna plurituberosa
18. Canna speciosa - Maas considers this to be Canna indica.
19. Canna stenantha

Canna hybridization has crossed many of the wild species in a very complex manner. Many epithets have been used in canna breeding programs leading to names such as Canna x hortensis, Canna x hybrida, and Canna x orchiodes. These have all been abandoned and for the sake of simplicity, all ornamental hybrids of canna are now properly called Canna x generalis. Usually, breeders do not mention the epithet "x generalis" when they write the name.

Canna Genetics & Breeding

Cannas first appeared in US gardens in the 1840s but they were not widespread until the 1890s. Much of the early breeding work with cannas occurred in France. The first prominent breeder was M. Théodore Année, a French diplomat who collected Canna glauca and Canna indica in Chile and based his garden hybrids on crosses of these two species. He improved the habit and leaf color but his cultivars sported wild-type flowers. Année released at least 20 hybrid lines by the 1870s with names such as Canna Annei-rosea, Canna Annei-rubra, and Canna Annei-marginata. Later catalogs referred to Canna Anneii and some early taxonomists have used the now invalid term Canna x annaei. Unfortunately, many of his hybrid lines have died out, but there are some modern hybrids with similar traits. The Année cannas were bred primarily for foliage attributes and are usually listed in the Foliage Group of ornamental Cannas. Année was also responsible for another popular breeding line of foliage cannas named for a German named Ehemann. These were primarily a cross between Canna iridiflora and Canna 'Warscewicsii' (aka Canna warscewicsii, Canna indica var. warscewicsii) and are also known as Ehemann Cannas, Canna 'Ehemannii', or the invalid name Canna x ehmannii.

From the 1860s to 1903, Pierre Antoine Marie Crozy bred hundreds of cultivars of cannas from Canna glauca, Canna indica, Canna iridiflora and Canna 'Warscewicsii' with a wide range of heights and flower colors. Some of these were known as French Dwarf cannas or gladiolus-flowered cannas due to their resemblance to (what else?) gladiolus flowers. Some of these were triploids, and only a few of his original cultivars survive today. These (and their modern offspring) have been assigned to the Crozy group of cannas. Crozy cannas tend to be the most cold-hardy of the garden cannas.

In the 1890s the German botanist, Carl Ludwig Sprenger, while working in Italy, crossed existing cultivars with the American native species Canna flaccida to bring bright yellow flowers into the gene pool. He introduced multicolored flowers that had yellow staminodes with red or brown splotches. These flowers often tended to resemble Cattleya orchid flowers because they had wide overlapping staminodes. Sprenger's cultivars were referred to as Italian Cannas or Orchid-flowered Cannas. They have also been known as Canna x orchiodes (or Canna x orchioides) which is no longer considered a valid name. These cannas have been assigned to the Italian Group of Cannas.

America also had its own crop of early canna breeders which include Antoine Wintzer and Dr. Van Fleet who together created over 100 cultivars from the 1890s to the 1910s. Their goal was to create pure color forms of rare colors, including yellow and white. Many of these crosses are still around today including the popular burgundy-leaved 'Wyoming'. At the same time, the West Coast plant guru Luther Burbank had his own canna breeding program.

The most prominent botanist of the 20th century doing research on canna genetics and breeding was Triloki Nath Khoshoo of the National Botanic Gardens of Lucknow in India. He performed in-depth studies of canna history, breeding and genetics during the 1960s and 1970s. The culmination of this research was the well known book, The Origin and Evolution of Cultivated Cannas.

Over the last 150 years, breeders have reduced the height of the plant, increased the flower size and staminode width, increased the length of the flowering period, improved the flower placement (higher above the leaves and more erect), improved flower durability, improved the cold hardiness, and produced self-cleaning plants (the spent flowers fall off automatically and do not need to be pruned).

Breeders are still looking for very pure bloom colors, especially white. Canna liliiflora has "white" flowers but is not cold hardy and it has been difficult to produce garden-worthy cultivars from it. Some are looking for blue or purple pigmentation in the flowers (as it currently does not exist). In addition, breeders want to increase the length of time that an individual canna floret lives, and the number of cultivars whose florets open during the day instead of the night. Improvements in both of these traits would result in plants that have more florets open at the same time and thus appear to be more floriferous. There is also the potential to improve the scent of canna flowers but flower scent is not the focus of many breeders.

Prominent modern canna breeders include; retired nursery owner and hybridizer Kent Kelly of Jonesboro, Arkansas; Reverend Curt Wallace of Delaware; Dr. Robert Armstrong of Longwood Gardens who had a large canna breeding program in the 1960s; Marcelle Sheppard of Texas; Jan Potgeither of South Africa; Bernard Yorke of Australia; and Dave Karchesky and Alice Harris of Pennsylvania. Plant Delights Nursery is happy to offer some of their best cultivars for sale.

Canna Culture

In their native habitat, cannas grow in shaded locations. However, in temperate gardens cannas need full sun. The more sun, the better. In the extreme southern US, the intense sunlight may bleach the flowers, but partial shade may help in these locations as well as in the desert Southwest, where the lower humidity and soil moisture may also cause foliar burning. Cannas will survive in a shady site, but they will not grow as profusely and the leaves (especially red or purple) may lose their color, defeating the purpose of growing them.

Cannas prefer rich, water-retentive, well-drained soils that are high in organic matter but will do fine in a wide range of soils. They prefer a pH around 6.5. Some cultivars have been bred to grow partially submerged in shallow water as well as in saturated soils. In drier planting areas, at least 1-2" of water per week is needed to keep cannas looking their best.

Like bananas, cannas are heavy feeders. Gardeners need to provide plenty of compost or organic fertilizer to keep their plants looking their best. Without adequate fertility or moisture, cannas look quite ugly. If your cannas look ratty during the summer, that's a sure sign that an extra shovel of manure is required. As long as you are using organics, it is impossible to over-fertilize a canna. You can cut ragged plants to the ground even in midsummer, add fertilizer, water, and they will quickly recover.

If you're growing your canna in containers, keep in mind that cannas are large plants and therefore need a large container. Any good potting soil will work fine. The plants will lose vigor as they become pot-bound. When that happens, lift the root-ball, divide the rhizomes and replant. Container-grown cannas will need watering once or even twice a day if grown outside, and it may help to stand the pot in a saucer of water. Provide a slow-release granular or water soluble fertilizer at full rate according to the instructions on the label.

Pruning is not necessary with cannas. As mentioned earlier, the old flower stalks will die and fade away on their own, but if you are a neat freak, feel free to cut them back. Be sure to remove the old spent inflorescences on cannas that produce viable seed to prevent unwanted seedlings that will vary from the original clone. In the fall, I like to let cannas die back on their own since the old foliage helps protect the rhizomes from winter cold.

Cannas are root hardy perennials in places where the soil does not freeze, and can survive air temperatures down to 0°F. They like really hot temperatures in the summer and perform well into the upper 90s. Canna rhizomes should be planted 2-4" deep after the last frost date and should not be planted after August, north of Zone 8. Potted cannas should be planted in the garden at the same level they were in the pot. A well-developed rhizome will have 3 or more eyes on it. We recommend that in climates where winter temperatures drop below 5 degrees F they be covered in fall with a 1' deep pile of shredded leaves. North of Zone 7b, you may be able to squeeze out another half-zone of hardiness by looking for a microclimate in your garden. Site your cannas along a south facing wall or other heat-retaining structure. Cannas are generally not bothered by high winds and do not need wind protection. Cannas form wide clumps so individual plants should be spaced 2-3' apart ... more for some of the more stoloniferous canna selections.

In colder climates, lift the tubers and store them indoors above freezing for the winter. When lifting the rhizomes, take care not to damage them, especially those cultivars that have long narrow rhizomes (like Canna 'Stuttgart'). Shake off the excess soil and store the rhizomes in peat moss to avoid dessication. Do not add any water or you will promote rotting. Dust the rhizomes with sulfur to keep away fungi and bacteria. Keep the rhizomes cool (below 50°F) but do not let them freeze. A garage, crawl-space, or basement is ideal. Make sure that the peat does not dry out too much during the winter. If the peat starts pulling away from the pot edge, add a little water. Prior to planting in the spring, wet the peat moss so that the rhizomes are turgid when planted.

Canna Propagation

Cannas may be propagated by division or by seed. When dividing the rhizome, lift it and remove any excess soil. Cut the rhizome into sections, each containing at least 3 "eyes" (prominent red buds). Single-eye divisions may survive but will take longer to produce a vigorous new plant. The best time to divide is when the rhizome is actively growing so that the new buds are easily seen.

Due to centuries of breeding, most of the commercial cannas are sterile and don't produce seed. Only those which are fairly close to the native species will produce viable seed. If you have several cannas, you can expect a wide range of variability in the seedlings since cannas are both self-fertile as well as out-crossing to other nearby cannas.

If your plants' seeds set, they will be held in warty quarter-sized capsules. When opened, the canna seed look like small, dark, ball-bearings. The seed coat is exceedingly thick and requires scarification for germination to occur. Part of the seed coat contains polyphenols which act as chemical germination inhibitors. They must break down or be washed away before germination will occur. Nick the seed coat with sandpaper, or a small saw blade until the light-colored tissues are exposed. Take care not to cut too deep and damage the embryo. There is a roughly circular spot on the seed called the "imbibition lid" near the hilum slit (the scar where the seed was attached to the fruit), which is slightly raised above the surface of the seed. The imbibition lid is the spot that naturally decomposes, falls off, and allows water to enter the seed. If you can find it, the imbibition lid is the best place scarify canna seed.

An alternative to scarifying the seed is the hot water method. Place the seeds in a cup and pour very hot (nearly boiling) water over them. The temperature shock causes micro-fissures in the seed coat which allows imbibition. Let the water cool naturally and soak the seeds in it for 24 hours. Warm water above 122°F (50°C) for 24 hours helps to loosen the imbibition lid.

Soak the scarified seeds in water for 24 hours and sow in a heated, well lit location. The soil temperature should be kept at 70°F (21°C) for best results. It is best to put each seed in its own pot because the new roots are very fragile and prone to tangling. Grow the seedlings at 60°F (16°C) until they have two or three leaves. Keep young seedlings indoors until the danger of frost has passed. Harden-off the seedlings by moving them outside to a protected location and gradually increase the light level and exposure to cooler temperatures until they are growing in full sun at outside temperatures.

Tissue culture has also been used to propagate cannas but it has been uneconomical compared to division due to the low perceived value of cannas. Because the level of virus in most modern cannas is so high, tissue culture has been the savior of many varieties that would have been otherwise lost.

Pests and Diseases

Because cannas are so tough, you would expect them to be free of pests and diseases in the garden, but this is not the case.

Slugs, snails, and Japanese beetles would fall into the range of minor pests on cannas. They damage the plants by chewing holes in the leaves or feasting on the flowers. Problems with slugs and snails can be virtually eliminated with good organic soil preparation and by avoiding the use of chemical fertilizers, which kill off many of the natural snail and slug predators. Similarly, Japanese beetles are seldom a problem when the plants are growing stress-free in well-prepared soils. If Japanese beetles do appear, they typically prefer only the canna flowers and can be easily picked up and subjected to the torture method of your choice.

Without question, the worst pest of cannas is a caterpillar known as the lesser canna leaf-roller, which is primarily found in the southern US. The canna leaf-roller moth lays eggs in the bud of the developing stalk. These hatching caterpillars use a sticky webbing to keep the leaf from unfurling, which protects them from predators and insecticide sprays. They feed and pupate inside the rolled-up leaf and can cause significant damage to the developing stalks.

Some cannas are more susceptible to damage by canna leaf-rollers than others. Typically, the closer to the species the cannas are, the less damage that we see. Canna glauca, for example, is virtually untouched. The key to controlling canna leaf-rollers is vigilance. Leaf-rollers can be a problem as early as spring, so keep a close eye for the first sign of webs holding the newly emerging leaves together. Opening the leaves and removing the offending caterpillars will work on a small scale, but in larger plantings, you can simply clip off the top half of the rolled leaf. Insecticides such as Dipel (Bacillus thuringensis) can be sprayed into the bottom half of the leaf so that it reaches the caterpillars. If the leaf-roller population is high, you may need to spray throughout the growing season, but as you reduce the moth population, the need to spray lessens. Again, the key is to monitor your plants and not allow the larvae to mature, which starts the cycle over again.

Aphids, spider mites, or whiteflies will rarely attack cannas in the garden, but can sometimes be a problem indoors or in a greenhouse. Again, stress reduction goes a long way to prevent such attacks, but when appropriate, these pests can be killed with insecticides (see your county extension office for recommendations). It is better to try to prevent insect infestation by removing dead foliage and providing a humid environment. Mice may eat the stored rhizomes and can be treated with baits or traps.

In hot, humid climates cannas can develop a fungal problem called canna rust. It forms rusty-orange colored pustules spread by splashed water on the back of the leaves which eventually turn black and die. Canna rust is difficult to control but there are fungicidal sprays that can prevent it from starting. Here at Plant Delights Nursery and Juniper Level Botanic Garden, we remove the rust covered leaves and destroy them ... they should never be added to your mulch pile!

Along with leaf-rollers canna viruses are the most serious cultivation problem. Canna viruses are easily passed from plant to plant by sucking insects such as aphids and then spread by unsanitary division techniques. Virus can cause spotted or streaked leaves, stunted growth, and distorted blooms. Low levels will not kill the plant but they may reduce its vigor. In most cases, low levels of virus are undetectable and unnoticeable, except during cool weather. High virus loads, on the other hand, can render cannas so unattractive, they must be discarded. Because cannas are often carelessly divided, viruses can easily spread and multiply. Cannas are also one of the few plants in which viruses can also be transmitted by seed. While many of the seed strains are fairly clean of virus, this is not a guarantee of a virus-free plant. There are several viruses that can infect cannas including Bean yellow mosaic virus, hippeastrum mosaic virus, tomato aspermy virus, cucumber mosaic virus, canna yellow streak virus, and most seriously, canna yellow mottle virus. Most canna cultivars tolerate a certain amount of viral load and will grow and thrive despite being infected.

As late as 2005, there were virtually no virus-free cannas grown in cultivation, but the savior came in the form of tissue culture. We had been trying to persuade labs to tackle the issue of cleaning up the canna virus in the laboratory and finally, Agristarts of Florida stepped forward. During the tissue culturing process the canna's sterile tissue is subjected to high heat which causes the developing plant to stretch. The stretched part of the new tissue is then re-cultured before the virus has a chance to re-infect it. Each new culture is then checked to make sure the virus isn't still present ... a process called virus-indexing. This is a time consuming and expensive process ($1000-$5000 per plant) since it often takes several tries to make sure the tissue is finally clean. Agristarts is continuing their work and it is our hope that other labs will join them in their goal to bring less virused stock to the market.

Despite selling clean stock, there is no guarantee that the plants will stay clean once they are exposed to the environment, but at least we've got a much better quality plant than we had available in the past. There is no cure for virus infections in cannas other than the procedure mentioned above or to destroy the infected plant.

Canna Species and Natural hybrids

Canna glauca (Glaucous Leaf Canna)

Here is a canna for folks who don't like cannas ... and for those that do! Canna glauca is composed of glaucus grey green narrow leaves, that are topped all summer with lovely buttery yellow flowers ... not as abrasive as some of the large flowered hybrids, but quite lovely. This vigorous spreader for the border may need to be contained in good soils ... a nice problem! (Hardiness Zone 7-10)

Canna glauca 'Panache' (Panache Canna)

Originally brought into the US by California sea captain Commander Bauman, it was passed around California until spotted by plantsman Herb Kelly, who named and introduced it to commerce. The narrow, pointed, grey-green leaves adorn the upright stalk to 6'. Atop the clump through summer and into fall are charming, narrow, salmon-pink flowers (darker in the center). This vigorous grower even spreads fast enough for you to share plenty. Canna glauca can grow in standing water or in regular garden soil. (Hardiness Zone 7-10)

Canna indica 'Red Stripe' (poss. syn: Canna indica 'Purpurea')

We have been growing Canna indica 'Red Stripe'in our test garden for a number of years, as visitors begged us to begin propagation. The 8' tall, thick stalks are home to large (nearly 2' long) leaves of purple with a dramatically contrasting green pattern between the veins. Topping, but not distracting from, the great bold foliage are stalks of small, brilliant red flowers ... a can't-miss addition to the border! (Hardiness Zone 7b-10)

Canna iridiflora (Peruvian Canna)

This species of canna has been used extensively as a parent in the creation of modern canna hybrids. This is an extremely tall plant (up to 16') with small, pendulous pink flowers that arrive late in the season. It is a native plant in high elevations of Peru, Columbia, and Costa Rica. (Hardiness Zone 7b-10)

Canna patens (Patens Canna)

Considered to be a synonym of Canna indica by Maas but a separate species by Tanacka. It is small sized with green ovoid foliage, a spreading habit, and triangular stems. The spikes of flowers are upright, yellow with a wide red margin. Its staminodes are long and narrow, edges regular, petals yellow, partial self-cleaning. It is fertile both ways, self-pollinating and also true to type. Tillering (running offsets) is prolific. (Hardiness Zone 7b-10)

Canna 'Tama Tulipa' (Tama Tulipa Canna)

This naturally occurring hybrid of Canna glauca and Canna indica was discovered by the folks at Yucca Do Nursery in Tamaulipas Mexico. Resistant to the canna leaf roller. The flower petals are bicolored with a central florescent red-orange color surrounded by golden-yellow. This is an 8. tall plant. (Hardiness Zone 7b-10)

Canna tuerckheimii (Tuerckheim's Canna)

This is an extremely tall species of canna that is almost never seen in cultivation. The leaves are quite large for a canna and the flowers are orange-red. Come take a gander at ours. You'll have to look up though because it is 12' tall! (Hardiness Zone 7b-10)

Canna Cultivars

Plant Delights Nursery is proud to have been the first to name and release several cultivars of Canna. The following list details our new plant releases: Canna 'Pink Sunburst', Canna 'Kansas City' (1998), Canna 'Nuance' (2004), Canna 'Thai One On' (2008), Canna 'Thai Rainbow' (2008).

Below is a short list of some of the interesting cultivars at Plant Delights Nursery and Juniper Level Botanic Gardens. We strive to grow only the most interesting and evocative specimens as well as some of the new plants on the market.

Canna 'Apricot Dream' (Apricot Dream Canna)

This color breakthrough in cannas comes from Kent Kelly of Arkansas. The sturdy, 3.5' tall, compact plants boast attractive grey-green foliage, topped with tremendous numbers of flowers from late spring until frost. The huge flowers are soft, pure buff-salmon with rose throat markings. This new introduction has been one of the top performers in our extensive canna trials. (Hardiness Zone 7b-10)

Canna 'Australia' (Australia Canna) (syn: Canna 'Feuerzauber')

We have grown a lot of purple-foliaged cannas but never anything like this. The deep burgundy-black foliage has a satin-like sheen, and the intense color holds superbly during the summer heat. The foliage rises to 4-5', topped with a magnificent display of large, shocking red flowers ... a true stunner. Thanks to canna guru Johnnie Johnson for sharing this coveted gem he obtained from New Zealand. (Hardiness Zone 7b-10)

Canna 'Bengal Tiger' (Bengal Tiger Canna) (syn: Canna 'Aureostriata' or Canna 'Pretoria')

Imported from India in 1963 by the Glasshouse Works guys, this is considered to be the most beautiful of cannas. The dramatic stalks of green-and yellow-striped leaves with a brilliant maroon edge grow to 6' and are topped in summer with bright orange flowers ... scrumptious! Canna 'Bengal Tiger' will also grow in water as an aquatic. (Hardiness Zone 7b-10)

Canna 'Cleopatra' (Cleopatra Canna)

I couldn't believe my eyes when they fell upon this canna at the Kunming Botanic Garden in China. Large purple blotches wove their way through the green leaves and into the flower stalks. If the flowers came from the purple side, they were red ... from the green side of the leaf, they were yellow ... sometimes from both ... you get the picture. This unstable and highly variable chimera is actually an old but hard-to-find cultivar called Canna 'Cleopatra'. We think it is time for a reintroduction of this fascinating attention-getter. Remove all solid green shoots to maintain the pattern. (Hardiness Zone 7b-10)

Canna 'Constitution' (Constitution Canna)

We think this is one of the most "designer-friendly" cannas we have ever grown. Instead of the typical gaudy colors we love, this sweetie from the famed Longwood Gardens breeding program is quite the opposite. The narrow foliage is a mysterious grey-purple color, making a perfect foil for the rich, creamy, light-pink flowers that top the clump. While this 5' tall plant is a good grower, it is not as fast to multiply as are most other cannas. (Hardiness Zone 7b-10)

Canna 'Durban' (Durban Canna)

This is from the 1980's wave of variegated leaf cannas. The reddish purple leaf is dramatically striped with yellow veins. In addition to the dramatic foliage, the plant is topped from late spring through late summer with stalks of large brilliant scarlet-red flowers for a combination that would make even the most flamboyant designer blush. Canna 'Durban' makes a great garden plant but does not multiply as fast as the other variegated leaf types. Some people say it is the same as Canna 'Phasion' but it is distinct in flower. (Hardiness Zone 7b-10)

Canna 'Ehemanni' (Ehemanni Canna)

This hybrid or selection of Canna iridiflora, first introduced in 1863, is quite different from other cannas in the trade. The large, cherry-red flowers on the 8-foot giant are held on arching pendulous spikes. We have found this to be a great, back-of-the-border choice due to its size, color, and floriferousness. Canna 'Ehemanni' has long been a crowd favorite at open house. (Hardiness Zone 7b-10)

Canna 'Ermine' (Ermine Canna) This Curt Wallace hybrid is still regarded as the closest to white (as judged by a team of color-blind nurserymen) that is available in the canna family. This 3' tall clumper is topped all summer with very large, creamy white flowers, flushed with pale yellow toward the center. Canna 'Ermine' will allow designers to create some exciting and distinctive new color combinations in the summer garden. (Hardiness Zone 7b-10)

Canna 'Florence Vaughan' (Florence Vaughn Canna)

They say that everything old is new again and nothing could be more true with canna lilies. Named after Florence Cropp Vaughn, Canna 'Florence Vaughan' was introduced from the famed Vaughan's Seed Company (now Syngenta) of Chicago in 1893, and just like the Cubs, it still has many loyal fans. Unlike the Cubs, Canna 'Florence Vaughan' is consistently good. This vigorous canna makes a stunning 6' tall clump, topped all summer with large bright yellow flowers highlighted with dramatic orange-red speckling. (Hardiness Zone 7-10)

Canna 'Freedom' (Freedom Canna)

Released by canna geneticist Dr. Robert Armstrong from his canna breeding program at Longwood Gardens in the 1960's. This canna belongs to the Conservatory Group which means that it is vigorous, early flowering, self-cleaning and easy to propagate. It has hot-orange flowers with a yellow throat. (Hardiness Zone 7b-10)

Canna 'Intrigue' (Intrigue Canna)

Designers love it, garden visitors love it, we love it ... so why are we sharing? This amazing canna, a 1978 seedling selection from California's Herb Kelly, is one of the most un-canna looking cannas we have grown. The very narrow, pointed, purple-grey foliage makes one of the most stunning accent plants in the garden. In addition, the narrow leaves and strong vertical habit make the architectural presentation of this canna most special. The 7' tall clumps are topped in very late summer with small orange-red flowers, but this baby is truly chosen for its wonderful form ... sort of like the babes of Baywatch. (Hardiness Zone 7b-10)

Canna 'Kansas City' (Kansas City Canna)

This unusual canna adds to the ever increasing line of variegated foliage cannas. From our plant-nut friend, Jim Waddick, comes this sport discovered in Kansas City, MO. The foliage has irregular 1" wide sectoral patterns, alternating green and chartreuse. In late summer, the clumps are topped with large bright butter yellow flowers. While I can't call this canna attractive, it is a curiosity and certainly a true collector's item. (Hardiness Zone 7-10)

Canna 'Mactro' PP 13,809 (Tropicanna Gold Canna™)

Yes, it's another new canna from the folks at Anthony Tesselaar ... reportedly a Canna 'Phasion' seedling from the breeding of New Zealand's Neil MacCormick. In appearance, it is similar to the Canna 'Bengal Tiger' with bright yellow-and-green striped leaves. The bright, luscious foliage makes a sturdy 4-5' tall clump, topped from midsummer until fall with flower spikes of large, bright orange flowers, each with a yellow border. Another difference is that the flower stalk is creamy white as compared to red in Canna 'Bengal Tiger'. (Hardiness Zone 7b-10)

Canna 'Minerva' (aka: Canna 'Nirvana' or Canna 'Striped Beauty')

This old hybrid is still one of the most popular of the variegated cannas today. Canna 'Minerva' makes a 5' tall stalk with brilliant white-and-green striped leaves. This vigorously multiplying canna is topped off with unique red flower buds that open to large, butter-yellow flowers ... produced all summer! When Canna 'Minerva' is fed well and kept moist, it is indeed a fantastic garden plant. (Hardiness Zone 7-10)

Canna 'Musafolia' (Banana Canna Lily)

If you are into the tropical look, don't miss growing the gigantic banana canna. Canna 'Musafolia' has a clouded origin (possibly related to Canna 'Edulis'), but what we do know is that it is one heck of a structural element in the garden. The 12-14' tall stalks are home to extremely large, banana-like leaves ... each green with a purple-red border. While Canna 'Musafolia' rarely flowers, the flowers produced are small, red, and pale in size compared to the foliage. (Hardiness Zone 7b-10)

Canna 'Orange Punch' (Orange Punch Canna)

"Amazing!" "I've never seen anything like it!" These are just a few of the comments from visitors about this Kent Kelly hybrid. Canna 'Orange Punch' is a compact, fast-multiplying canna, topped from spring until frost with intense bright orange flowers with a yellow throat. From its Canna iridiflora background, the flowers are held in long pendent racemes instead of the typical upright spikes. If you like bright gaudy colors, this unique new canna will quickly become one of your favorites! (Hardiness Zone 7b-10)

Canna 'Pacific Beauty' (Pacific Beauty Canna - syn: Canna 'Semaphore')

If you haven't noticed, we are lovers of the truly tacky and gaudy, and Canna 'Pacific Beauty' takes tackiness to a whole new level. You will love the luscious grey-purple foliage, but what will really shock you is the intense orange flowers that top the 6' tall clumps. These are not your typical orange flowers but are more of a fluorescent pumpkin-orange ... it is truly a WOW canna! (Hardiness Zone 7b-10)

Canna 'Phasion' PP 10,569 (Tropicanna Canna Lily)

This incredible recent introduction from Jan Potgeither of South Africa is a sport of the ever-popular Canna 'Wyoming'. Even without flowers, you would surely grow Canna 'Phasion' for the foliage ... purple with dramatic stripes of yellow and red, evenly spaced throughout the leaf. Atop the 7' tall stems are wonderfully gaudy, shocking orange flowers throughout the summer ... indeed, this is the Howard Stern of the plant world ... guaranteed to get your friends talking! (Hardiness Zone 7b-10)

Canna 'Pink Sunburst' (Pink Sunburst Canna)

The rave of the plant world is our 1996 introduction we named from Sunburst Flower Bulbs in South Africa. This dazzling canna is the hottest thing since summertime in Miami. Canna 'Pink Sunburst' is similar to Canna 'Bengal Tiger' (yellow-and green-striped leaves), except the variegated leaves have a reddish-pink cast. The 3' tall dwarf, rapidly multiplying mound of foliage is topped all summer by large salmon-pink flowers. We have finally been able to get the virus cleaned from our stock, which has restored the original vigor. (Hardiness Zone 7b-10)

Canna 'Pink Sunrise' (Pink Sunrise Canna)

From Kent Kelly's marvelous breeding program comes one of the most incredible flowering cannas that we have ever seen. Each 4' tall clump is laden with massive flowers of soft apricot with blushes of light rose and yellow radiating from the throat. The color combination of pinks and oranges in the flowers changes constantly throughout the day ... very cool! (Hardiness Zone 7b-10)

Canna 'Reine Charlotte' (Reine Charlotte Canna) (aka: Canna 'Königin Charlotte')

This deliciously tacky canna hybrid from the late 1800s is still one of our favorites. The small, brilliant red flowers, outlined with a wide band of bright yellow are held atop 4' tall stalks throughout the summer months ... a real showstopper. (Hardiness Zone 7b-10)

Canna 'Stuttgart' (Stuttgart Canna)

Here's another vigorously growing variegated canna everyone is talking about. This German introduction was discovered and named by the late Bob Hayes of the Brooklyn Botanic Garden. The bold, green-and-white blocked patterns on the foliage make this a stunning centerpiece in any landscape. The white portions of the foliage tend to burn in sun, so we recommend light shade and plenty of moisture. In late summer, the plants are topped with inconspicuous, small peachy flowers ... WOW!!! We have been told adding extra magnesium (Epsom salts) to the soil will help prevent the foliage burning ... we will see. (Hardiness Zone 7b-10)

Canna 'Thai One On' (Thai One On Canna)

This amazing Canna glauca hybrid (possibly with Canna iridiflora) was brought into the US by Texan Margie Brown, who purchased it sans name from a roadside nursery south of Bangkok. The 6' tall stalks of glaucous leaves are topped, starting in summer, with peachy-orange buds that open to lovely, somewhat pendent fleshy-pink flowers (RHS 48D) ... the best pink-flowered canna we've ever grown and extremely leaf-roller resistant. Like Canna glauca 'Panache', it multiplies quite rapidly when grown in moist, rich soil. Thanks to both Mary Elliott and Steve Lowe for independently sending it our way. (Hardiness Zone 7-10)

Canna 'Thai Rainbow' (Thai Rainbow Canna)

For something truly unique, we are pleased to introduce Canna 'Thai Rainbow', which offers a unique leaf variegation pattern (reportedly radiation induced). Canna 'Thai Rainbow' forms a 6' tall, rapidly multiplying clump of narrow leaves that are banded green and cream with a purple flush that is particularly evident on the leaf edges. The clumps are topped with small but bright red-orange flowers throughout the summer ... looks and grows like a variegated form of Canna 'Intrigue'. (Hardiness Zone 7b-10)

Canna 'Tropicanna Black' PPAF (Tropicanna Black Canna - syn: Canna 'Lon01')

This new canna was introduced without a valid cultivar name ... sorry guys. 'Lon01' isn't valid, so we have renamed it Canna 'Tropicanna Black'. Understanding that cultivar names should be real words must be harder than I thought. Canna 'Tropicanna Black' is the latest addition to the splendid black foliage canna selections. The shiny dark purple leaves, which are wider but not as dark as Canna 'Australia', make a nice 4' tall clump, topped with stalks of bright vermillion-red flowers from early summer until fall. (Hardiness Zone 7b-10)

Canna 'Valentine' (Valentine Canna)

Grab your sunglasses, 'cause you've never seen a color this bright. I've grown lots of red cannas but never anything like this. Unlike most of the orange-red flowers, Canna 'Valentine' boasts eye-popping flowers that are more of a true bluish red than anything else on the market. Because of its dwarf size, Canna 'Valentine' makes a perfect attention-getter, both in containers and in the garden. (Hardiness Zone 7b-10)

Conclusion

Cannas are worthy garden perennials for any southern garden, and with a little extra care, a great addition to gardens in northern areas too. This flowering perennial brings an exotic beauty to sunny garden sites with its showy flowers and tropical (sometimes very colorful) leaves. Go on-line today and buy one of these incredible, exotic plants for yourself. Plant it in your garden, sit back, and enjoy the show. Don't let anyone tell you that cannas are passè or hard to grow. Ignore them and just remember, "You Canna if you Wanna"!

You may be asking yourself, 'What is the best canna for me?'

If you want an incredible variegated plant, try Canna 'Phasion', Canna 'Stuttgart', Canna 'Bengal Tiger', Canna 'Pink Sunburst', or Canna 'Thai Rainbow'.

For dramatic purple foliage choose Canna 'Australia', Canna 'Intrigue', .Constitution. or Canna 'Tropicanna Black'.

If you want eye-popping saturated flower color, try Canna 'Minerva', Canna 'Pacific Beauty', or Canna 'Orange Punch'.

For a more demure look choose the pastel colored Canna 'Ermine', Canna 'Thai One On', or Canna glauca 'Panache'.

If you want to party like it's 1849, select a Victorian era foliage Canna, such as Canna 'Musafolia' or Canna indica 'Red Stripe'.

Whichever one you choose, you will get a winner.

References

Avent, Tony (1992), Leaves that Light up the Garden -- Variegated Plants,

Originally published in the Fall 1992 issue of Fine Gardening Magazine.

Avent, Tony (1997), Gardening With Hardy Tropicals,

Originally published in the News & Observer, May 24,1997.
www.plantdelights.com/Tony/tropicals.html

Canna News, List of Cultivar Groups

cannanews.blogspot.com/2007/04/canna-cultivar-groups.html

Cooke, I (2001), The Gardeners Guide to Growing Canna,

Timber Press, Portland OR

Khoshoo, T.N. & Mukherjee, I. (1970), Genetic-Evolutionary Studies on Cultivated Cannas,

Theoretical and Applied Genetics, Vol. 40, Pp. 204-217.

Tanaka, N. (2001), Taxonomic revision of the family Cannaceae

in the New World and Asia, Makinoa ser. 2, 1:34.43.

Tanaka, N. et. al. (2009), Karyological analysis of the genus Canna (Cannaceae),

Plant Systematics and Evolution, Vol. 280(1-2), Pp. 45-51