Seed production

I have been asked to explain in as simple a way as possible, how Cannas produce seed. Let's start by identifying the parts of the flower that are involved.

In the picture left, the central upright petal is the style, the female part of the flower. At the tip of the style is the stigma. The stigma is slightly sticky, and it is where the pollen must end up if it to fertilise the female ovaries, which are located below the style and out of the picture. The stickiness is caused by a sugar-type solution, which serves to both secure the pollen and also provide it with the energy to grow a pollen tube down to the ovaries.

To the left of the style is another petal called the stamen, and attached to the stamen is the anther, the sack where the pollen grows, becoming fertile at the same time as the flower opens.

The pollen in the picture has already been squeezed out of the anther, the pressures involved with the flower opening have the effect of squeezing the pollen onto the style. The cultivar in the picture is now waiting for a pollinator to arrive, it may be a bee, or a hummingbird, whichever, it is attracted to the flower by the prospect of drinking nectar, a sugary solution, produced in the base area where the petals all join together in a twirl, called the tube. But remember, there is not such a thing as a free meal! In return, the Canna expects to be pollinated.

The pollinator pushes its head down into the folds of the petals and drinks from the nectar, in the process it will attach the pollen you see in the picture to its body or bill, and then transfer it onto the stigma as it backs out again, a self-fertilisation. Alternatively, if it had visited another Canna prior to this one, it will have pollen attached to it from that one, and on its way down to the nectar that might be transferred onto the style, so performing a cross fertilisation.

In wild species, the anther is situated a little higher than the one in the picture and the pollen is automatically squeezed onto the stigma, that is what we mean when we say a species is self-pollinating.

Finally, at the bottom of the picture you can see the only real petal in the picture, although this article has referred to petals elsewhere, they are really staminodia, but more on that another time.

Summer splits

An article in this months R.H.S. "The Garden" caused me to review what I had done over the last few years and wonder if splitting Cannas can be done better. Although dividing perennials is usually a job for spring or autumn, recent findings suggest that, for some plants, summer division is better.

Firstly, although we treat Cannas as perennials, in reality they do not need rest and in their native environment they grow for 52 weeks of the year, only slowing down if temperatures go too high. In temperate climates we know that they will be destroyed by freezing temperatures and so we store them in a safe environment over the winter and early spring, until the threat of frosts is past. The risk of too high temperatures is not a problem.

Cannas do not have a true state of dormancy, they simply have an ability to survive bad weather and growing conditions in the wild, things such as fires and drought. The large store of starch in the rhizomes means they have the energy to start over again. Anyway, after subjecting them to intense distress over the winter months, we then split them and start them into growth. In the process we always have a high number of casualties, not surprising when you think that they have been in a state of extreme stress for six months, then we aggravate that by splitting them and expect them all to grow a new root system as well as top growth for us to admire.

The garden trade knows that if they don't sell the rhizomes in the spring, then they won't sell many later. So, it makes sense that the trade cleans, splits and packages over the winter for a spring sale. The trade normally sells them in packs of three, so the customer has a high chance of getting something to grow, even if the rhizomes have been subject to bad storage and display conditions.

For gardeners with an established collection of rhizomes, it may be better to plant the established, semi-dormant clumps back in the ground and then, when they are flourishing again, with a proper root system, to split them. What make me start thinking about this? For the last few years I have been trading plants with another enthusiast in July/August, and I have been splitting the rhizomes for exchange the week before his arrival. Within weeks, my own plants have recovered and thrown lots of new, fresh growth and my gardening friend has lost none of his newly potted plants.

It is noticeable that the splitting has added new zest to the plants, but it is probably just the fresh food in the new potting compost or the bone meal that I add first before replanting in the ground, and the handful of fertiliser afterwards which creates that effect, and makes them appear to outperform their companions.

Anyway, I have determined to give it a try next year, and instead of working in the cold and damp of the winter in a poly tunnel, I will leave our collection alone and just replant them in May, and then do the splitting during the summer, when I can enjoy the exercise and weather. For those not convinced, why not try splitting just one of your plants this summer and try it for yourself?

The tiger wins the stripe award

Canna 'Bengal Tiger' is a variegated Italian Group canna cultivar; plant height 190 cm; foliage height 140 cm; upright stems and gently spreading leaves; ovoid foliage, background of green (RHS 137A); veins variegated yellow (mostly 13B), but paler in places (13D); maroon edge to leaf; staminodes, labellum and stamen bright orange (28B) blushed a darker, reddish (32A) in places; yellow (15A) on edges; stigma deep orange-red; petals strongly flushed red. The flower has a crumpled silk appearance; seed and pollen has very low fertility levels; rhizomes thick, up to 3 cm in diameter. It is a mutation, as are all variegated Cannas, believed to be a sport of C. 'Wyoming'.

There were also a large number of very similar cultivars, many were obviously identical and just synonyms. But synonyms of what?

In 2005, at Claines Canna, we decided to grow as many of these plants as we could obtain alongside each other, to establish once and for all if they were different. We obtained specimens of:

1. Canna 'African Yellow' from Holland
2. Canna 'Bengal Tiger' from Philippines
3. Canna 'Pallida Variegata' from Holland
4. Canna 'Panaché' from France
5. Canna 'Pretoria' from UK
6. Canna 'Pretoria Dwarf' from USA
7. Canna 'Striata' from RHS, Wisley
8. Canna 'Striped Wonder' from USA
9. Canna 'Tropicanna Gold'TM from UK

All of the participants in the trial were grown in identical conditions in 20 litre pots filled with Murphy's peat based, general puropose compost. They were grown alongside each other but moved around regularily to allow direct comparisons with each other, and they were all on the same automatic watering system. None enjoyed any growing advantage over the others.

It was noted that all of the individual specimens had variations in colours, both foliage and blooms. Not normally noticed, but when closely examined they became obvious. The colours in the foliage varied, and the size of the stripes was also variable. The flower colours varied considerably, having a base of bright orange, and some with orange-red blush or even markings and many had a yellow rim or even a widish border.

What was also noted was that the variations were not only across different specimens, but on the same plant! The size of the staminodes was also variable, even on the same stem!

Although claims for C. 'Tropicanna Gold'TM are for a large amount of golden yellow around the edges of the blooms, we never noticed enough yellow to justify the claim that it was different from the others, but C. 'African Yellow' was impressive on that score, and had a a yellow rim on all the flowers it produced. Canna 'Pretoria Dwarf' was the same height as all of the other trial participants, and that name seems to be misleading.

Our conclusion was that they were all the same plant, just many different names and a propensity to be variable, as are so many of the Italian Group, where the introduction of the wild species C. flaccida created a volatile mix. As this is reputed to be a mutation of C. 'Wyoming', it is not surising that it is a little unstable. The other possibility was that it may be vulnerable to the quantity and quality of sunlight and water when the foliage and flowers were being formed.

Next, we examined Canna history to establish what was the correct name for this cultural wonder. Investigation revealed the cultivar originated as C. 'Bengal Tiger' at the Agri Horticultural Society of India, Bengal in the 1950s, probably as a result of the Radiation experiments that took place at that time.

It was later transported to the African continent, by Sydney Percy-Lancaster, the Secretary of the Society, when he retired to Rhodesia, taking with him the Alipore Canna collection, originally founded by his father in 1890. Hence the synonym of C. 'Pretoria' when it was later discovered by US plant collectors in the late 1960's growing in that contintent; in spite of having already been imported directly to the USA from Bengal, India in 1963 by Glasshouse Works, again as C. 'Bengal Tiger'.

Under the synonym of C. 'Striata' it was awarded the 'Award of Garden Merit' (AGM) in the 2002 Canna trials held at RHS Wisley, but that name belongs to an early Foliage Group cultivar dating from 1868, and still being grown under that name in Europe.

The list of synonyms (probably incomplete) that we have discovered for for this cultivar are:

• Canna 'African Yellow' - confined to Europe
• Canna 'americanallis var. variegata' - confined to USA
• Canna 'aureo-striata'
• Canna 'Damascus Road' - confined to Southern USA
• Canna 'Imperialis'
• Canna 'Kapit'
• Canna 'malawiensis variegata'
• Canna 'Pallida Variegata' - confined to Europe
• Canna 'Panach'
• Canna 'Panaché' - confined to France.
• Canna 'Pretoria'
• Canna 'Pretoria Dwarf'
• Canna 'Striata' - this name belongs to an early cultivar from 1868, still being grown in Europe.
• Canna 'Striped Wonder'
• Canna 'Tropicanna Gold''™
• Canna 'Zebra Summer'
• Canna 'Zebra Sunset'

When is a Canna not a Canna?

A Canna certainly is not a Canna when it is Thalia dealbata.

Commonly known throughout the southern states of the USA as "Water canna" or powdery thalia, it is a rhizomatous marsh or marginal aquatic perennial that features long-stalked canna like foliage and violet blue flowers.

It is a tall plant, 2-3 metres (6-10'), that lends a tropical flavour to ponds and water gardens. It is native to swamps and ponds from South Carolina to Florida west to Missouri and Texas. It is rare to Missouri, its distribution being limited to swampy areas in the southeastern lowlands region.

The species features paddle-shaped to lanceolate-elliptic blue-green canna-like leaves 50cm (18") long, on petioles to 70cm (24") long. Foliage is dusted with white powder. Violet flowers appear in branched open panicles 20cm (8") long, atop of scapes typically rising well above the foliage to 2 metres (6') , less frequently to 3 metres (10') tall. It blooms July and August. The genus name honours a 16th century German physician and naturalist, Johann Thal.

As far as cultivation is concerned, Thalia dealbata grows in wet soils or in shallow water in full sun. It grows best in organically rich loams. Plants are considered winter hardy to USDA Zones 6-10. In St. Louis, plants are best grown in containers either sunk in wet mud near the water line or submerged in up to 60 cm (2') of water.

Plants may also be grown in wet boggy areas. Containers covered by 50-70 cms (18-24") of water will generally overwinter in place. Consider bringing other containers indoors to a greenhouse or other frost-free area with bright light. For plants grown in wet boggy soils, just cut back stems and mulch heavily in winter. The plant has no serious insect or disease problems.

The real origins of Canna

The question has often been asked, "How can we be so sure that Cannas originated in South America?" We do know that the first Cannas introduced to Europe were C. indica L., and although they all came to Europe from the East Indies, they originated from the American continent. Charles de l'Ecluse, who first described and sketched C. indica in his Histoire des plantes rare observées en Espagne (history of rare plants observed in Spain), published in 1576, indicates this origin, and states that it was given the name of indica, not because the plant is from India, in Asia, but because this species was originally transported from America: "Quia ex America primum delata sit"; and at that time, one described the tropical areas of that part of the globe as the Western Indies; English speakers still call them the West Indies.

Much later, in 1658, Pison made reference, in his Histoire naturelle du Brésil (natural history of Brasil), to another species which he documented under the vulgar name of 'Albara' and 'Pacivira', and which resided, he said, in the shaded and damp places, between the tropics; this species is Canna angustifolia L., (later reclassified as C. glauca L. by taxonomists).

Without exception, all Canna species that have been introduced into Europe can be traced back to the American continent, and it can be asserted with confidence that Canna is solely an American genus. If Asia and Africa provided some of the early introductions, they were only varieties resulting from C. indica and C. glauca cultivars that have grown for a long time in India and Africa, but not from species growing in a spontaneous state.

The penultimate argument to the assertion that Canna is a South American genus is the fact that it is certain, as it is pointed out by Lamarck, in his Botanical Encyclelopédie, that "Cannas were unknown to the ancients, and that it is only after the discovery of the New World, that they made their appearance in Europe; whereas if the soils of India or Africa had produced some of them, they would not have waited until the 1860’s, to make an entry into the European gardens."

The final argument is that Canna seeds have never been discovered by archeologists in the Old World, and the hard shells of Canna would have ensured that some would have survived.

Crazy about Crozy

In 1862, Pierre-Antoine-Marie Crozy, a partner in Avoux & Crozy, at La Guillotière, Lyon, France introduced his first Canna hybrids, they were C. 'Bonnetti', C. 'Plantieri' and C. 'Rodleisii'. They were well received by the enthusiasts of the time, but nothing would have told them what would happen in the following forty years.

Monsieur Crozy's goal was to turn Cannas from being primarily a foliage plant, with pretty but insignificant flowers, into a floriferous plant that could compete alongside any other genera in the flower beauty stakes. How well he succeeded can be judged by the fact that by the time of his death in 1903 the Canna was the most popular garden flower in both his native France and in the USA, where it even outsold roses.

Canna 'Bonnetti' has staminodes that are 45 mm. length and 13 mm. breadth, and by the time of his demise new cultivars were being introduced where the size had been increased to 66 by 35 mm, and this was achieved purely by selective breeding. The different colours and colour patterns in bloom and foliage were introduced by crossing his hybrids with other species, such as C. iridiflora. Basically, Crozy raided the species to supply him with any new feature he required.

The most famous of the cultivars introduced by Crozy was Canna 'Madame Crozy' (see the print), and this was later used by both Luther Burbank in California and Carl Sprenger in Italy to cross with the species C. flaccida to produce the first of the Italian Group Cannas.

Monsieur Crozy has been referred to as both Antoine and Antonin, the latter being a common nickname for persons called Antoine. He was also called Crozy aîné, which is the French for "elder", however, it is reasonable to assume that he was not called by that nickname until late in life. Incidentally, there are canna cultivars called C. 'Papa Crozy', and C. 'Antonin Crozy', sometime refrred to as C. 'Antoine Crozy'. The third of his christian names is the French version of Mary, which was a name commonly given to both genders in those days.

Antoine Crozy was succeeded by his son, Michel Crozy, who died only five years later at the tender age of 37 years, thus ending one of the most important and dynamic periods in the history off Canna.

It can be seen from this posting, how important the species are to us. The species collectively have provided everything currently found in our cultivars. There does seem to be an opportunity to introduce some new blood. Also, interesting seedlings can be obtained by using some of the early Foliage Group cultivars, produced nearly 150 years ago as the pollen parent, most are self-pollinating and would need to be emasculated if they were used as seed parents.

Chemicals can be dangerous

The rain was pouring down, but as a true Germanic I knew my duty. My knees were sodden as I knelt down and planted out the collection into this suddenly wet garden, while the rain poured down. After I finished planting out, having added a handful of bonemeal underneath each plant, as a final solution, I went around with pellets of Growmore and scattered them around on the surface.

Next day I went to visit this wet setting and about 10 plants, out of the 150 I had planted, were in a desparate state, having leaves that were bent and which had given up. All tne others had survived the continous rain. So why had the others had their foliage destroyed at the stem?

It took a while to work it out, and all sorts of explanations provided red herrings before the solution. When I threw the Growmore capsules around, some had lodged in the joint between the stem and the leaf. Careless distribution, because Growmore has to be on the ground to have the effect it is used for.

As soon as the 20 hours of continous rain arrived the Growmore pellets lodged between the stem and the leaf began to dissolve. The volume that dissolved was too much for the stem, and it rapidly disintegrated.

So, when applying pellets to your young cannas, please be careful. Keep them on the ground and ensure that none lodge on the joint between the stem and the leaves, otherwise, when the rains arrive they will dissolve the concentrated feriliser and overwhelm the leaf joint.

Describing Canna size, foliage and flower colours

Classification by Size

All cultivars in the Canna Names database table on the Yahoo! Canna group, and the Claines Canna website, are classified as being one of the following five sizes: Giant, Large, Medium, Small, Miniature.

Giant - over 3m (9'9")

This category is confined to just a few extraordinary specimens, such as C. 'Sky Hawk', C. 'Marabout' and C. 'Omega'. Just describing them as large does not describe their extraordinary prescence and extraordinary architectural significance. These plants are serious replacements for Musa and other senior architectural plantings.

Margaret and C. 'Sky Hawk' in mid-summer, by Autumn it was much taller.

Large - from 2m (6'6") up to 3m (9'9")

Amongst the large category of Cannas are bedding favourites of Gertrude Jeykell and Christopher Lloyd, such as Canna 'Wyoming' and C. 'Roi Humbert'.

Medium - from 1m up to 2m (3'3" - 6'6")

When Herr Walter Pfitzer of Stuttgart, Germany, EU, was producing his new cultivars around the years 1880-1910 they were referred to as Dwarf Cannas, because they were so much smaller than the large specimens hybridised by Année and the other early Canna hybridisers. However, by the standards of many modern day cultivars they are positively on the large side. So the dwarf label attached to Herr Pfitzers cultivars should be treated as being relative, rather than absolute, and we have quietly dropped using it as no longer being appropriate. However, even that statement is not definitive. The Pfitzer company kept on breeding new Canna long after the death of its founder and when we reach the 1920’s most of their new cultivars fall under the category we call 'Small'.

Small - from 0.6m (2') up to 1m tall (3'3")

These are the modern day gardeners preferred canna cultivars. Capable of providing both significant foliage and flower displays, versatile enough to grow in pots as well as in borders. The garden centres preferred size, as they can fit onto display benches that the larger ones rapidly outgrow.

Miniature - up to 0.6m tall (2')

This category is confined to just a handful of truly miniature Cannas, referred to by Sydney Percy-Lancaster as Table Canna, meaning that they could be used in small vases on dinner tables as replacements for the normal orchid type flowers beloved by the restaurant industry.

Classification by Leaf Colour

We have found that the following 3 classes is sufficient to catalogue the collection:

• Green
• Dark
• Variegated

Classification by Flower Colour

Colour is a little more difficult to classify, because of the many shades and permutations, however, the following general classifications work for us:

• Red
• Orange
• Yellow
• White
• Pink
• Multicoloured
  

Canna 'Trinacria Variegata', a record holder

Because cannas developed for nearly a century on separate continents, without a lot of communication between them, the result has been countless synonyms. It is proving interesting in reconciling the synonys and creating some order out of the name chaos. The record holder for the number of synonyms has to be Canna 'Trinacria Variegata'.

It is a small Italian Group cultivar; variegated foliage, oval shaped, white margin, spreading habit; round stems, coloured green + purple; flowers are reflexed, yellow and white, staminodes are large, petals red; seed is sterile, pollen is low fertile; rhizomes are long and thin, coloured white; tillering is average.

Eye-catching variegated leaves, with large butter-yellow blooms, marked by this plants signature - a white stripe down the centre of each petal forming a white cross. Variegated leaves of green with pale yellow variegation parallel to the veins. There are several different strains with varying degree of variegation distinction, but the flower type and its size seems uniform between them all.

Nurserymen folk legend has it that in 1923 a consignement of Canna 'Trinacria' rhizomes was despatched to Siam, now Thailand, from a nursery in California. When it arrived at its destination and was grown out it was found to have variegated foliage. A sample was returned to the nursery with a demand for a refund or replacement as it was not what had been ordered.

This mutation was probably caused by the extreme conditions endured in transport from California to Thailand in the days before air travel. The cultivar was examined in the 1960's by Dr. Khoshoo, who stated that this was not a chimeral mutation.

After much research, I can confirm that the earliest reference to this cultivar is as C. 'Trinacria Variegata' in Sydney Percy-Lancaster's book, "An Amateur in an Indian Garden", 1927. Under the International Rules of Cultivar Nomenclature this has to be treated as the correct name, and all of the others are to be treated as synonyms.

The record number of synonyms discovered so far are:

1. C. 'Bangkok'
2. C. 'Bangkok Yellow'
3. C. 'Bankocki'
4. C. 'Bankok'
5. C. 'Christ's Light'
6. C. 'King of Siam'
7. C. 'Minerva'®
8. C. 'Nirvana'
9. C. 'Striped Beauty'
10. C. 'Striped Beauty of Bangkok'
11. C. 'Stripped Beauty'
12. C. 'variegata'
13. C. 'Variegated'

An amusing aside, about three years ago, while perusing spring bulb offerings in our local Blooms gardening centre I encountered a packet of Canna rhizomes labelled as Canna 'Striped Beauty', the cultivars favourite synonym, but something had gone badly wrong with the picture (above) on the packaging. The foliage was correct, and definately C. 'Striped Beauty', but the flowers belonged to a totally different Canna, they were yellow with orange spots, possibly C. 'Golden Girl', or something like that.

Now, the flowers of C. 'Trinacria Variegata' are held about 25 cm (10 inches) above the top of the foliage. The packaging designer had obviously decided to improve on nature and superimpose a lot of flowers just above the top of the foliage, the most desirable position, and had done so very professionally, you can't see any joins, but had got confused and used the wrong flowers! An object lesson to all who try to improve on what nature gives us.

Finally, I have to confess that my favourite synonym is C. 'Stripped Beauty', it leaves the imagination boggling! The web site using that name probably meant C. 'Striped Beauty', but made a spelling error. It has displayed that name for over three years without noticing, and nobody seems to care to mention it to them!

Musaefolia Peruviana, genetic volcano!

It has long been asserted by the Royal Horticultural Society that C. 'Musaefolia' does not flower in the United Kingdom. This caused us some consternation, as two of the three types in our collection do give flowers very late in the season and also give seed. However, the largest and most majestic, which we now know is C. 'Musaefolia Peruviana' Année, had never flowered for us. It is obviously that variety of the Musaefolia's that the RHS were referring to when they passed that comment.

Well, the combination of the RHS assertion, our own observations and a quest for adventure and danger was enough to stir us into accepting the challenge, plus the extra electric bills over the whole winter! So, three years ago we kept the plant growing over the winter and in May and June of the following year it flowered for us outdoors.

The flowers were a revelation, being orange instead of the red colour we had been led to expect, and they also provided us with some interesting sights. Unfortunately, being May, there were no other Canna flowers to try and pollinate, and although self-pollinating, we had no seed from the flowers.

But most amazing was the genetic volcano that was revealed. Two of the three flowers had an extra staminode, see middle photo, and one of them also had two anthers, one on either side of the stamen so that they did not interfere with each other. The photograph above shows another flower with two separate stamens, each equipped with a single anther. That photograph was taken using flashlight, so the colour on that photograph has been corrupted.

To summarise, we enjoyed the following variations:

1. Four staminodes, one labellum, one stamen, one anther, one style.
2. Three staminodes, one labellum, one stamen, two anthers, one style.
3. Three staminodes, one labellum, two stamens, each with its own anther, one style.

Contrast that to the normal canna cultivar, where we have 3 staminodes, 1 labellum, 1 stamen, 1 anther and 1 style. As the style is connected via the tube to the ovaries it unlikely that we would ever see two styles, but I suppose that even that variation might be possible.

The variations are of significance to hybridisers, as it would be interesting to cross this Foliage Group cultivar with our modern day Crozy Group cultivars and attempt to introduce extra staminodes into our current garden varieties.

Musaefolia complex unravelled

Canna 'Musaefolia cultivars belong to the Foliage Group of Cannas. In the 1800's it was sometimes attested that Canna 'Musaefolia' was a species. However, our two modern day taxonomists, Professor Maas and Dr Tanaka, do not acknowledge this as a species, or even attempt to specify which species it is a synonym for. Therefore, we must treat it as a cultivar. In the first work devoted to Canna, Le Canna, authored by M. Chaté in 1867 with the co-operation of Monsieur Théodore Année, we were provided with the first written description and details of origin. This is also the authority as to the spelling of the variety, and we know that the two spellings commonly seen, namely C. 'Musafolia' and C. 'Musifolia', are incorrect and are just synonyms .

The first work dedicated solely to Cannas, by E. Chaté, Le Canna, son histoire, son culture, published by Libraire Centrale d'Agriculture et de Jardinage in 1867, stated that:

This species was formerly described in the English, Dutch, and German horticultural journals under the name of C. ''excelsa''. It was named musæfolia by Mr. Année, who introduced it into France in 1858, from the resemblance of its leaves to those of the Musa or banana-tree. It reaches a height of more than 8 ft. and has green, downy stems, and very large, oval, green leaves. Flowers small, orange-yellow. It is a tender species without rhizomes, and requires to be kept constantly growing. Peru.

Nothing that matches this description exists today, all known Cannas have rhizomes or tubers. It is either extinct, a hybrid, or a mutation that was mistaken for a species, as happened to over 100 others that were mistaken as species in the early days of domestication. Whichever way, it cannot be proven to be a species, and taxonomists will not acknowledge anything without evidence.

However, we do know that the early hybridisers, led by Monsieur Année, crossed the original import and produced cultivars, some of which still live on.

Canna 'Musæfolia Hybrida'

Resembles the species C. 'Musæfolia', but the stems and leaves are thicker and of a deeper green. Chaté E. (1867)

A tall Foliage Group cultivar; dark green foliage, very large, broadly oblong shaped, maroon margin, spreading habit; oval stems, coloured green; flowers are upright, self-coloured salmon-red, staminodes are small, edges regular, style is red, petals purple with farina, fully self-cleaning; fertile both ways, not true to type, self-pollinating, capsules round; rhizomes are thick, up to 3 cm in diameter, coloured purple; tillering is prolific. Introduced by Théodore Année, Passy, France, EU in 1860.

Canna 'Musæfolia Minima'

Leaves of a whitish green, badly set. Flowers small, orange brown. No rootstocks. Introduced by Théodore Année, Passy, France, EU in 1860. Chaté E. (1867)

All Canna grown today have rhizomes or tubers, this hybrid must now be considered to be extinct.'

Canna 'Musæfolia Peruviana'

Stems green and downy, 5 ft. to 6½ ft. high. Leaves very large, wide, green. Flowers small, orange. Rootstocks very small. Chaté E. (1867).

A tall Foliage Group cultivar; green foliage, very large, broadly oblong shaped, maroon margin, spreading habit; oval stems, coloured green; spikes of flowers are open, red-orange with orange-red spots, staminodes are medium size, edges regular, labellum is gold flecked, stamen is gold with orange markings, style is orange, petals yellow, fully self-cleaning; fertile both ways, not true to type, self-pollinating, capsules round; rhizomes are thick, up to 3 cm in diameter, coloured pink and purple; tillering is prolific. Introduced by E. Chaté et fils, sentier Saint-Antoine, Saint-Mandé, Paris, France, EU. in 1862.

This does not normally flower in northern climates, but if kept growing over the winter in a heated greenhouse or conservatory it will happily bloom either in late spring or late summer.

Canna 'Musæfolia Perfecta'

Stems from 5 ft. to 6½ ft. high. Leaves broad, very firm, of a handsomish whiteish green. Flowers small, yellow. Roots fiberous, without rootstocks. Introduced by Théodore Année, Passy, France, EU in 1862. Chaté E. (1867)

The description states without rootstocks. No such cultivar exists any more and must be considered extinct.'

Canna 'Musaefolia Rubra'

Stems dark red, 6½ ft. high. Leaves dark purple-red, oval, very large. Flowers small, salmon-red. Rootstocks very tender, with fibrous roots. Introduced by Théodore Année, Passy, France, EU in 1862. Chaté E. (1867).

A tall Foliage Group cultivar; dark green foliage, very large, broadly oblong shaped, maroon margin, spreading habit; oval stems, coloured green; flowers are upright, self-coloured salmon-red, staminodes are small, edges regular, style is red, petals purple with farina, fully self-cleaning; fertile both ways, not true to type, self-pollinating, capsules round; rhizomes are thick, up to 3 cm in diameter, coloured purple; tillering is prolific.

Canna 'Musæfolia Grande'

The original five musaefolia hybrids have been recently joined by this cultivar, which may be a synonym of one of the five above, or a new hybrid. It is regarded by many enthusiasts as a magnificent specimen and is becoming increasingly popular.

A giant Foliage Group cultivar; green and purple variegated foliage, large, oval shaped, maroon margin, branching habit; half-round stems, coloured green + purple; spikes of flowers are upright, self-coloured orange-red, staminodes are long and narrow, fully self-cleaning; fertile both ways, not true to type, self-pollinating, capsules globose; rhizomes are thick, up to 7 cm in diameter, coloured purple; tillering is prolific. Introduced by Herb Kelly, USA, from Venezuala. The earliest reference to this is Kelly's Plant World, California, USA. 1989.

So, there we have it. The descriptions come from the pen of one of the hybridisers, and his book was reviewed by the great Monsieur Année himself. To summarise, there was one species, possibly extinct, but more likely growing away happily in the wilds of Brazil and Peru away from preying eyes. There were five F1heritage hybrids, two of which are almost definately extinct, as nobody admits to growing Canna hybrids that have no rhizomes, and the three remaining hybrids, still growing in our gardens. Plus C. 'Musaefolia Grande', the modern cultivar. More postings on these surviving specimens to follow...

Polyploidy in Canna

Each cell of a canna plant naturally has 18 chromosomes, or 9 pairs. These plants with their paired chromosomes are termed diploid, from the Greek word for "double".

The pollen and ovules (eggs), are formed through a process called meiosis, which results in the production of cells that have only half the parent organism's chromosomal material; these cells are termed haploid, from the Greek word for "half". The haploid pollen and ovule join in fertilisation to form the new diploid cell that eventually becomes the offspring organism, and jointly provide the 18 chromosomes.

Sometimes, however, the process of meiosis fails, and pollen or ovules are produced that have the full complement of parental chromosomes; this type of cell is called a non-reduced gamete. When such a reproductive cell participates in fertilisation with a haploid cell, an event that does not occur as easily as normal fertilisation, the resulting offspring has three sets of chromosomes instead of the normal two and is termed triploid. When both pollen cell and ovule cell have the diploid chromosome number, the offspring has four sets and is termed tetraploid. All organisms with more than the normal number of chromosomes are collectively called polyploid.

Polyploid cannas tend to be larger, stronger, more substantial, and more persistent in every respect. This has obvious advantages in any growing context.

The offspring of a triploid and a diploid parent is a tetraploid. Such a cross usually produces few or no normal seeds. With their 27 chromosomes, triploid cannas are difficult to cross with other cannas.

Although in other plants it has been possible to create cultivars with a higher chromosome level, the tetraploid seems to be the limit of the Canna, even after extensive laboratory experiments by Dr Khoshoo and his colleagues. Tetraploids can occur naturally as the resulting failure of meiosis, as described for triploids, if there are irregularities in the formation of both parent's reproductive cells. They can also be produced vegetatively under laboratory conditions.

Fertility

Diploid 18 chromosomes Triploid 27 chromosomes Tetraploid 36 chromosomes Pollen Fertility: 89.8% 66.1% No data Seed Fertility: 5-10 per capsule Totally sterile Occasional

Tillering capability

As a rule, triploid cultivars tend to have fewer tillers (underground rhizomes) than diploids, although C. 'Roi Humbert'', an Italian Group triploid, is an exception.

Foliage

In general, the diploid cultivars have rather large but relatively narrow leaves in comparison to the triploids. The leaves in triploids are thicker than in diploids.

Flowering Period

Being a perennial plant, Canna has the potential to bloom throughout the year, however, under the hot subtropical conditions, as found in its native environment, most of the elemental species and cultivars are unable to bear the heat in the hottest month or so. For the remaining period, weather conditions being suitable, both elemental species and cultivars show a variable response. In the main diploid cultivars will flower for nine months while triploids will flower for 10 months. Tetraploids have the potential to flower for longer periods.

Flowers

In the main, the sterile cultivars have larger flowers than those that are fertile. Triploids in general have larger flowers than diploids. The largest triploid, C. (Italian Group) 'Wintzer's Colossal', has a flower diameter of 21cm, not quite as large as the early nurserymen alleged in their catalogues, but nevertheless a large flower.

Conclusions

The phenotype transformation from wild to the cultivated condition has involved reduction in plant height, change in form and colour of leaves, spikes well above the foliage, free flowering, erect flowers, increase in flower size and colour diversity, increase in thickness of flower petals, durability of flowers and self-shedding capability. In addition, polyploidy has been affected, so that:

Diploids

Studies by Dr Khoshoo have shown that over 80% of cultivars are diploid. The majority of these belong to the Crozy Group which are rather small in size but produce an abundance of relatively large flowers.

Triploids

Triploids make up about 15% of cultivars and the properties of them varies dependant on whether they are Crozy Group or Italian Group, i.e. the occurrence of C. flaccida in their background.

Tetraploids

Stray tetraploids have occurred, but the slow growth and lack of fertility has meant that these are freak exceptions.

It is speculated that triploidy appears to be the highest effective level of polyploidy achieved in ornamental canna. This is also true of cannas yielding starch (Agriculture Group). Perhaps cell size increases to an optimum at this level and higher levels, as well as aneuploid progeny, are not possible because of total seed sterility. Therefore, unlike hyacinth, also a vegatively reproduced ornamental, unbalanced progeny is not possible with canna.

References

Origin and Evolution of Cultivated Cannas, T.N. Khoshoo and I. Guha (Neé Mukherjee)

Was the eruption of Mount Vesuvius the cause?

Mount Vesuvius, outside Napoli, Italy, is one of the world's most dangerous volcanoes. The volcano has an eruption cycle of about 20 years, but the last eruption was in 1944. The volcano is rated as one of the most dangerous in the world due to the close proximity of millions of people. Famously, in 79 AD an eruption of the volcano destroyed Pompei and its remains are a popular tourist attraction south of Napoli. However, the eruption that interests us took place on 4th April, 1906, when Dr Carl Ludwig Sprenger, a German botanist and a partner in the world renowned horticultural establishment of Dammann & Co. of San Giovanni a Teduccio, Napoli, found himself the victim of another eruption of this volcanic monster.

Sprenger was the creator of many Cannas, and the Italian Group is named in deference to his production of new cannas. The eruption buried his plants under volcanic ash, destroying hundreds of his best specimens. Some survived, and the establishment attempted to continue, but the following year when Sprenger was offered the role of supervisor of the Kaiser's garden at Achilleion, a garden with a palace on the island of Corfu (Kerkyra), which he accepted and moved much of his plant material to the palace gardens.

In 1909 the Royal Horticultural Society granted its Award of Merit to the last known Canna produced by Sprenger, Canna 'Roi Humbert'. Sprenger said at the time that this Canna would surprise the horticultural world. It is the result of a backcrossing of C. 'Madame Crozy' x C. 'Italia', the latter being C. 'Madame Crozy' x C. flaccida.

Canna 'Roi Humbert' is an Italian Group cultivar; it has bronze foliage, ovoid shaped, with a spreading habit; distinctive stems, are coloured purple; flowers are open, turning to reflexed, self-coloured tomato-red, staminodes are large, edges irregular, fully self-cleaning; seed is sterile, pollen is sterile; rhizomes are thick, up to 3 cm in diameter, coloured purple; the tillering capability is good. It was confirmed to be a triploid, see Khoshoo, T.N. & Guha, I, Origin and Evolution of Cultivated Cannas, Vikas, India. It has been sold under several synonyms, including C. 'King Humbert', C. 'King of Prussia', C. 'New Red', 'C. 'Red King'.

As Sprenger predicted, it did cause a sensation, when sometime later, C. 'King Humbert', as it is known in much of the English speaking world, prided a chimera mutation, which Luther Burbank, California, USA, called Canna 'Yellow King Humbert'. That has gone on to acquire many synonyms of its own, notables being C. 'Cleopatra', C. 'Goldkrone', C. 'Harlequin', C. 'Queen Helena', C. 'Queen of Italy', C. 'Yellow Humbert'. It may be that these are not synonyms at all, but separate mutations; however, our plant material is so mixed that we cannot identify such circumstances.

Canna 'Yellow King Humbert' is a medium sized Italian Group cultivar; foliage green, but often variegated purple markings and occasionally whole leaves purple, oval shaped, spreading habit; oval stems, coloured green + purple; flower clusters are cupped, spotted, colours yellow with red spots, often large red markings and occasionally whole staminodes or even the whole flower red, staminodes are large; seed is sterile, pollen is sterile; rhizomes are long and thin, coloured white and purple; tillering is prolific.

But the story does not end there, as Canna 'Yellow King Humbert' also has a trick up its sleeve, when it mutates again and produces a new cultivar, similar to its original mutation parent, the first of these secondary mutations was named C. 'Red King Humbert'.

It is recognizably different from C. 'Roi Humbert', having retained the cupped shape flower of C. 'Yellow King Humbert' and the colour is a scarlet red, rather than the tomato-red of the former. It has repeated that trick on several occasions and we now have similar cultivars resulting from this further mutation.

Maybe they are all the same plant, but until a scientific analysis of these specimens is performed, we will not know. In the meantime, I intend to enjoy them all. Other names that spring to mind are C. 'Zulu Maiden', C. 'Red Cleopatra'', C. 'Patrick's Red'.

A mutation can be caused by copying errors in the genetic material during cell division, by exposure to radiation, chemical mutagens, viruses, or under cellular control during meiosis or other extreme stress conditions. Was the hot volcanic ash of Mount Vesuvius the cause of the chimeric mutation found in Canna 'Roi Humbert'?

We will never know for certain, but the dates of these events are such that it is highly probable that our favourite Canna chimera is a direct result of the eruption of Mount Vesuvius in 1906.

Red foliage cannas

I was always under the impression that early canna cultivars had green foliage, and much later crosses introduced the dark foliage; a feature that so many love in Cannas. However, my reading has revealed that cannas with red foliage have been in evidence since the early 1800's. Rubra is the Latin word for red, and we have several interesting cannas in our collection that carry that name.

The first is a species called Canna rubra (Willd.). Johnson's Dictionary of 1856 describes it has having "Red flowers indoors in December, originating from the West Indies and first introduced to England in 1820." Modern taxonomists have treated Canna rubra as being a synonym for Canna indica, and at least one authority feels that it was probably a duplication of Canna indica var. indica Warscewiczii. That same species was used by Monsieur Crozy in his development of the floriferous Crozy Group of cannas.

The earlier reference to flowering in December was due to the fact that in those days, in England, Cannas were grown indoors in glass buildings, with heat provided by coal heated stoves, hence the name given to Cannas, and other expensive tender imports, at that time of stove plants. Cannas were considered to be too tender to grow outdoors at all, and only people with wealth could consider growing them.

Rather than using glass houses, Monsieur Théodore Année and the other French hybridisers quickly adapted the technique of lifting and storing rhizomes in the winter months and growing out again next spring, once the threat of frost had receded. The rhizomes descended from Canna indica and C. glauca proved to be amenable to that process, and so we remain today. That technique is now used by most Canna growers resident in temperate zones. As we all know, Canna 'Annei; was the first canna cultivar, but Monsieur Année went on to produce many more cultivars, amongst them were some with dark foliage.

We have early records of three Foliage Group cultivars raised in the mid 1800's, the first was Canna 'Rubra Perfecta', (perfect red) raised by Théodore Année, Passy, France, EU in 1861. In Subtropical Gardening, Robinson 1868, it was described as having stems dark-red, from 5 ft. to 6½ ft. high. Leaves dark-red, rayed with purple. The flowers are of medium size, orange-red. Rootstocks are dark-red, and conical. It seeds freely.

Canna 'Rubra Superbissima' (superb red) was another new cultivar from Monsieur Année, also in 1861, and Robinson described it as having stems dark purple-red, very thick, from nearly 6 ft. to 6½ ft. high. It’s leaves are broad, round, purplish-red, with a metallic lustre. Flowers of medium size, light orange-red. The rootstocks are brownish, very thick, conical, and crowded together. It was stated to be one of the finest metallic-red-leaved Cannas. In addition, Thompson's Gardener's Assistant, edited by Thomas Moore, 1892, described it as being 5 to 6 feet in height; leaves very broad, of a rich purplish red colour, with a metallic lustre in the sun. This is a free grower, and one of the best of the red-leaved kinds. At that time in canna history the floriferous cultivars from Monsieur Crozy were the fashionable rage, so the mention is all the more remarkable as Moore obviously felt that this was an outstanding specimen.

Finally, Canna 'Rubra Nerva', (red ribbed) was raised by E. Chaté and sons, sentier Saint-Antoine, Saint-Mandé, Paris, France, EU. in 1862. It was described by Robinson as having stems dark-red, from 3½ ft. to 5 ft. high. Leaves long and narrow, lance-shaped, reflexed, dark-red rayed with purple. It had large flowers, of a cinnabar red. The rootstocks are dark-red, very long, conical, and cylindrical. Robinson went on to say that this cultivar resembles a weeping willow.

This strongly resembles our own cultivar, C. 'Russian Lance' (left), which was a seedling from C. 'Russian Red'. We are growing C. 'Russian Red' next to C. 'Rubra Superbissima' for comparison this year, as there seems to be no difference between them. We also intend to supply a specimen of the latter to the National Canna Collection, so that Keith and Christine Hayward can make a judgement as well.

References:

1. Le Canna - E. Chaté et fils, 1867
2. Subtropical Gardening - Robinson 1868
3. Thompson's Gardener's Assistant, Edited by Thomas Moore, 1892