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Buying and growing canna

I have recently become fond of cannas but don't know the first thing about how to look after or culivate it. I have just a couple of questions

Can they be grown from seed?
Can they be left outside all year round?
How much attention do they require?


  • fidgetbonesfidgetbones Posts: 16,526
    Yes. No. Lots

  • InglezinhoInglezinho Posts: 568
    1.No. 2.No. 3.No more than roses. They are the best tropical plant to grow in UK.

    1.Growing from seed takes years till you get a flowering size plant and because most garden Cannas are hybrids, they will not come true ie. not be as good as the original, especially the variegated forms. The best way to propagate them is to take a sharp knife and cut off a new shoot vertically ie. into the ground so you get the roots. Best time early summer, but it's not too late to have go. 

    2.Treat them as you would any tender plant. Lift the plants before the first frost with a fork. Cut off any stems that have already flowered to ground level - they will not flower again. Pot them up into a fairly dry, sandy compost and keep them frost free over winter. If you keep them warm ( the best way) they will continue to grow and produce decent foliage plants. However, if they do get cold, keep them very dry. This is the best way to ensure their survival. I strongly advise this method for the variegated varietes but the purple-leaved ones are good also, but watch out for spider mires on the underside of the leaves.
    I find a good way of dealing with this pest, which spoils the look, but doesn't kill them, so if you get it - symptoms, dry shrivelled leaves - you can still plant them out next year - IS, if we get a mild spell during winter - put them outside. The (relative) cold will decimate them.

    Plant them outside after the risk of any frost. I keep a number in pots all the year round - with winter protection of course - as they make superb patio plants, though needing a lot of watering and fertilizer. They are hungry and greedy plants, Fidgetbones is right in this respect, so if grown this way will need to be repotted ideally every year.
    Warning: you can get hooked... Good luck - Ian ([email protected])

    Everyone likes butterflies. Nobody likes caterpillars.
  • punkdocpunkdoc Posts: 13,276
    Not wishing to cause trouble, but you can get them to grow from seed and flower in the first year, even in the north, but you do need to germinate with heat, early in the year and then feed and water well.
    There are ashtrays of emulsion,
    for the fag ends of the aristocracy.

    S.Yorkshire/Derbyshire border
  • LynLyn Posts: 21,340
    edited August 2019
    At the OP is asking about growing them from seed, this may be more of interest than how to propagate them from cuttings!.

    I’ve grown them from seed, as @punkdoc says, and they do flower in the first year,  you need to soak the seed then chip them but every one germinated.
    not difficult at all.
    Ive never had a propagator, they jut germinated on the kitchen worktop as all my seeds do.  
    In the autumn just lift them, still in their pots into a greenhouse, conservatory or similar and away they go next year.
    My daughter lives in Cornwall,  hers are in the open ground, they just stay there and always come up next year, she can’t get rid of them.  They’re never watered or fed, they live in her gravel garden and do very well, I’ve always associated them with a plant that you can just leave to get on with it. 

    Gardening on the wild, windy west side of Dartmoor. 

  • Hostafan1Hostafan1 Posts: 33,700
    edited August 2019
    @Inglezinho , that's total tosh.

    Species cannas are easily grown form seeds. C Warscewiczii will get to 1m tall easily in the first year AND flower. They're often grown as "bedding" and replaced each year. 
    I've had fallen seed germinate with no help from me whatseover.

    They can be left in the ground if you live somewhere where Dahlias can be left in the ground. I'm in bog wet Devon and I've found some popping up which I've missed clearing in Autumn.

    So long as they're in fertile soil  which doesn't dry out they'll be happy. Give them extra water and extra feeding and they'll be VERY happy.

    I've never has spider mite,( or mires ) on any canna, but beware of virus, spread by aphids.
  • dpatel2130dpatel2130 Posts: 179
    Growing from seeds. These are the plants resulted from the seeds. I put the seeds in pots app six weeks ago in general purpose compost. In ground since last week. 
  • dpatel2130dpatel2130 Posts: 179

  • LynLyn Posts: 21,340
    That’s very good, it’s just a shame that the slugs like them so much.
    Gardening on the wild, windy west side of Dartmoor. 

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