As long as the days are mild and the nights don’t freeze all the plants in the Exotic Garden will just keep going. Last week I talked about growing Gingers for late autumn colour but my absolute favourites and an absolute must at this time of year are the Cannas. They are essential plants for the exotic border as they are big, brash and totally over the top giving a tropical look to the border.
More than 200 hundred cultivars have been created over the last 100 years or so with some now almost impossible to get hold of; never-the-less, there are dozens still available to the discerning gardener. Unfortunately with popularity comes disease and over the last ten years or so many retailers of Cannas have been selling virused plants and tubers which must be avoided like the plague as it distorts the leaves and stunts growth quickly spreading to other plants. This year I have been ruthless with all my stock discarding anything that looks vaguely virused and obtaining a good selection of new plants from growers that guarantee that their plants are virus free.
The common name for canna is ‘Indian shot’ as the round black seeds were allegedly used as ammunition for shotguns in the British Colonial period, mostly in India.
Here at the Exotic Garden, Canna rhizomes are started off in late winter to early spring in a cool greenhouse and finally planted out in late spring to early summer, where they will normally start flowering by midsummer. They also make spectacular container plants. It is essential to feed them well with well-rotted manure and Blood Fish and Bone if you want your cherished plants to grow and flower well. Watering and feeding these stunning tropical’s ensures that they grow quickly giving you a fantastic show all summer, right through to first frost.
During the winter months, unless you live in a warm frost free winter location the stems should be cut down after the first frost has blackened the leaves and the tubers then stored in their pots or for those in the ground dug up and stored dry in trays of chipped bark or something similar at a minimum of 5C (41F).
Cannas vary considerably in size and stature, from the very small such as Canna ‘Lucifer’, which grows to no more than 1½ft high, to giants like C. ‘Musifolia’, which can easily reach 9ft or more especially if the summer is warm like the one we have just had. Most cannas are green leaved, though a good percentage of plants have leaves in various shades of pewter-purple-maroon – bronze to almost black, and a few are truly spectacular with vivid variegation such as ‘Pretoria’ and ‘Durban’. The flowers on the specie cannas tend to be small where as many of the cultivars have large blowsy flowers in many shades from yellow, pinks, red to white, and many are bicoloured.
There are far too many to mention here so I will write about a few of the twenty five or so grown here at the Exotic Garden. Canna ‘Striata’ for instance also known as ‘Pretoria’ and ‘Bengal Tiger’ stands out as being one of the most heavily variegated, having large leathery paddle-like leaves of deep green with bright yellow striations, topped with large Orange gladioli-like flowers. Sometimes the flowers have a yellow edge and are referred to as Tropicanna ‘Gold’.
The other well know cultivar is ‘Durban’ , as it is probably the most ridiculously variegated of all the Cannas, making it an absolute must for the summer garden if you can find virus free plants! The foliage is red-plum coloured, striped and feathered with strawberry pink. The large flowers are bright mandarin orange.
‘Black Knight’ is a choice plant with elegant darkly-bronze leaves. The flowers are deep-red and large, contrasting well with the foliage. It is an excellent specimen Canna; or used in mass plantings, growing to around 6ft plus.
‘Cleopatra’ is a ‘chaemera’ – it can’t decide what colour it wants to be! Some flowers are yellow with red spots, while others are all-red, and some are a mixture of both! Often, petals are half red and half yellow spotted .The foliage is also indecisive – usually green, but occasionally a purple streak will appear. Despite the confusion, this is an excellent and very exotic Canna which grows to about 5ft.
‘Musifolia Grande’ is a big one! The name ‘Musifolia’ means banana-like, as the leaves are very large indeed, growing up to 3ft long and 1ft across. Each leaf is green brushed with red and a distinct red-purple border. The stems are thick and broom-handle like. The small red flowers are rarely produced in the UK as our summers are not long enough though you are rewarded with sheer size, as it can reach a whopping 10ft tall in one season!
My favourite Canna this year is ‘Orange Punch ‘, an absolute stunner, growing to from 3-4ft tall with green foliage and the brightest orange flowers with yellow centres forming racemes that arch over. The flowers are not the largest in the canna group but makes up for it by flowering continuously all summer often twice as much as most other varieties. In most cases it is the first and last canna flowering. I can safely say ‘Orange Punch has been in flower all summer long!
Another new one for me this year is ‘Blueberry Sparkler’, an absolutely fabulous Canna with purple leaves and blue-grey undersides, making the perfect foil for the sturdy, medium pink flowers. This new selection is tall, slender, and full of grace unlike some of the other bolder foliaged cannas.
For sheer flowering power nothing can beat ‘Whithelm Pride’. This gem has been in flower since July and is still going strong, with upright dark blue-green foliage with darker purplish edges. The large candy-pink looking stunning when planted en-masse forming a haze of pink right through until the autumn frosts cut them down.
There are a least a dozen more I would like to add to this list, but alas no room to mention them here so if you would like to see them why not visit the Exotic Garden this weekend.