 |
| Cleaned Rhizomes |
In countries near the equator the canna is a 52 week of the year growing plant, but once we arrive in climates that have frosty and freezing periods then the canna becomes a perennial and humans have devised strategies to enable our tropical plants to survive and prosper.
Canna growing habits
Unlike bulbs, cannas do not hibernate over the winter, instead they are still ticking along and need protection from the elements.
They have one thing going for them, and that is thay have a large store of energy in their rhizomes, and most can survive for a long period without photosynthesis. This means that we can reduce their size to manageable proportions by removing their stems and their roots. The garden centre and mail order nurseries have long taken advantage of this, and package bare canna rhizomes in breathable packets with a little growing media to make it look suitably horticultural.
Many beautiful canna cultivars have been lost as their rhizomes and root systems do not render themselves to this type of treatment. The most obvious are our Aquatic Group cultivars and the wild water species, which all have long thin rhizomes which have been adapted to anchoring the plant in water, but which do not store the same volume of energy, in the form of starch, as the terrestrial cannas.
Weather: Only ground frost
Growing in the soil
If the soil does not freeze, then in such temperate areas cannas can be left in the ground all the year round. After frost destroys the foliage, cut plants back to 4 inches, enough to be able to get a firm hand grip later, if ever needed. Add a healthy layer of manure, leaf mulch, or straw in the autumn to protect rhizomes from the cold as the plants overwinter in place. Alternatively protect with a layer of fleece, but make sure the fleece is firmly anchored, as winds may disturb it and expose the canna plant to extreme cold.
Growing in pots
Cannas grown in pots should be brought indoors for winter, either into a garage or basement, alternatively under the greenhouse bench is a traditional winter home. Keep them dry (do not water, just spray to keep moist) until spring’s nighttime temperatures are consistently above 10°C. (50°F.), typically after the tulips have bloomed in northern areas. Only then move them outside for the summer. if they cannot be brought indoors then an alternative strategy is to wrap the pot with a layer of bubble foam and tie it tight with string, covering the top of the pot with more bubble. Place the pot next to the outside wall of the house to gain the little heat emitting from your home.
Weather: Frozen ground
In areas where the ground freezes it is necessary to dig up cannas growing in the soil in the autumn and bring them inside for the winter. After cutting the canna back to 4 inches, dig out the rhizome with a garden fork, I always avoid using a spade for this task as it is inclined to damage outlying rhizomes. You can avoid damaging the rhizome by digging about 1 foot away from the stem, but in crowded beds after a good growing years that will probably not be practical. The remaining stems act as a handle, so that you can gently loosen the soil and lift out the clump.
Store and divide next spring
At this point you have two alternatives, you can put the clump along with the clinging soil in a plastic sack and store in your garage or cellar, or under the greenhouse work bench is traditional, and deal with cleaning and splitting next spring.
Divide immediately and store
Alternatively, you can shake of the soil now and divide the clumps into separate rhizomes, each with at least one growing eye. Leave the rhizomes to cure in the sun or in a garage or closet for a few days to dry off a little and help them resist rot. They now need storing overwinter in a dry environment, so wrap each rhizome in newspaper or a paper bag, along with a small amount of dry growing medium, such as peat moss, to absorb moisture and help prevent rot. They can now be stored in boxes or seed trays (flats) in racks. Obviously rhizomes stored this way take up less space than those still in soil clumps.
Storage conditions
Store cannas over the winter in a dry place where the temperature will not drop below 4ºC. (40ºF.) Often, this is a basement, attic, or garage. Check the rhizomes a couple of times over the winter to make sure that they don’t dry out. Mist with a bit of water, as needed. If you find rot, cut it away or discard the entire rhizome.
Early spring
Those undivided clumps stored in plastic sacks can now be tackled, shaking of the soil and dividing the rhizomes into separate growing eyes. Any rot must be removed immediately, as that is cannas worst enemy. I dip any ends that have been cut of into sulphur powder. The rhizomes that you wish to grow-on can be potted up into 1 litre pots (5 litres for the large Foliage Group) in basic growing medium as there is no need for food at that time.
When the conditions are right, the canna will use the energy stored in the rhizome to create leaves and new roots. This is the main reason that you should not judge a canna leaf quality for the first few leaves that unfold, as those leaves are developed using stored energy and not the full photosynthesis energy cycle.
Spring has arrived!
When spring’s nighttime temperatures are consistently found to be above 10ºC. (50°F.), that is the time to replant outdoors or replant in full-size pots. Make sure each small pot, or divided piece, has at least one eye; as from it a new stem will grow. Blooms should appear in 10 to 12 weeks.
Comments
Post a Comment