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Overwintering Cosmos tuber

  • Overwintering Cosmos tuber

I intend to over winter my Cosmos atrosanguineus Chocamocha tubers. They have flowered beautifully over summer and as the specimens I bought were not cheap I'd like to give it my best shot rather than have to replace next year. Anyone have experience or tips to share.

Comments (8)

  1. Grower

    Rachel the Gardener

    I haven't tried to overwinter this plant myself, but Crocus.co.uk say "In autumn after the foliage has died back reduce the stems to within 5cm (2in) of the roots. Lay in a tray of soil or compost and over-winter in a frost-free environment until early spring"

    I would take this to mean that you would dig up the tubers, like we do with dahlias: the RHS site says "in cold areas lift tubers before first frosts and keep frost-free over winter." which would seem to agree with it.

    Presumably the idea of the tray of soil or compost is, as with dahlias, to prevent the tubers from drying out completely, while at the same time avoiding having them damp enough to go mouldy, so when Crocus say "lay in a tray" I would assume they mean that you would need to cover the tubers up, not lay them on top of the soil!

    Hope this helps?

  2. Grower

    Angie's Garden

    Thanks Rachel, that was the advice I found too. I had hoped I may get away with wrapping in newspaper like I do with my Begonia tubers but will follow advice given and have them covered with compost. Wish me luck!

  3. Grower

    Rachel the Gardener

    Good Luck!

    Make a note to let us know in spring if it worked.....

  4. Grower

    Angie's Garden

    I will do.

  5. Grower

    Alistair young

    i heard you can do this with nicotiana sylvestres

  6. Grower

    Angie's Garden

    You should give it a go if you are growing it next year Alistair. You've nothing to loose by trying.

  7. Grower

    BR2 Agapanthus and More

    I've had Cosmos atros.. growing outdoors in 1 litre pots for some while now, and have survived last 2/3 winters, even with snow and frosts - with only minimal shelter from a wooden box, here in Bromley, Kent.

    Best of luck though with your variety.

  8. Grower

    Angie's Garden

    Thanks. More often than not it is the wet that sees things off in winter here BR2, They will be coming out of storage next month so not long to wait to see if my attempt was a success.


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