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dahlias overwintering

Nanny BeachNanny Beach Posts: 8,716
Tried them a few years ago, following Monties instructions, dig up after first frost has blackened the folliage, etc, they just withered up,( I have a friend who is rubbish at gardening, hangs his upside down in a garage, they survived!  My garage is in a block in the next road, full of tools, and they would be forgotten)This year I grew a lot, some from seed, first time and they did really well, some are 3 feet tall, they have all been gorgeous, obviously, cost me a lot of money, desparate to keep them, I live in Est Sussex, 10 minutes by car from the sea, what I want to know has anyone in my neck of the woods actually managed to mulch them and leave them in.  One tip I did get from a Dahlia specialist grower/shower from Garden Weekly, was pot them up in the spring, cover them to exclude light for 7-10 days, and yes, the came up much quicker this time.


  • FairygirlFairygirl Posts: 54,794
    I'd have thought you could leave them in the ground where you are, NB.
    How about lifting some and leaving a few that you have duplicates of, and see what happens ?
    Have you got a shed or cold frame you could leave the lifted ones in? Once they're dried off, you can leave the tubers in a bit of compost, in pots or trays,  so that they don't get bone dry. 
    It's a place where beautiful isn't enough of a word....

    I live in west central Scotland - not where that photo is...
  • JemulaJemula Posts: 193
    They should overwinter in the ground OK with a mulch in the south east. The problem I found with doing this was that when they started shooting in the spring they were attacked by slugs and snails no matter how hard I was trying to protect the young shoots and slug hunting at night. So I gave up on that and lift them after the frosts, potting up in early spring and planting out after last frosts when they are a nice size.  
  • Nanny BeachNanny Beach Posts: 8,716
    Fairy, I think I only have duplicates of a couple, most were unusual varieties bought at these gardens that are open to the public.Got 3 greenhouses, potting shed, cold frame is already full, 2 of the greenhouses are full, havent got everything in yet, its been so warm, there are a lot and they will take up a lot of room, but I would hate to loose them.Yes Jemula, when I first put out the ones I bought from Sarah Raven, the b***** slugs munched the tops off with the flower buds, they didnt touch the rest of the plant, so I made sure they following ones were really big before I planted them out, that seemed to do the trick, although we did slug patrol.
  • edited October 2018
    I’m in Kent,15mins from coast but in a town. I planted Dahlias for the first time last year and because I’m lazy just left them in the ground mulched with bark compost.

    They came up amazingly this year which I was surprised by as they did get covered in snow!

    They are planted deep and my garden is south facing but does get cold in the winter as we are at the bottom of a hill.

  • FairygirlFairygirl Posts: 54,794
    Snow insulates plants though, AlliumpPS - unless they're soaking first, in which case they tend to freeze. Snow falling on fairly dryish ground will create a layer of warmer air round plants.  :)
    I should have added that a good layer of mulch over them will help insulate them, NB, as has been said. However,  like the snow, insulation only works if you aren't trapping cold and wet. If you mulch directly over a wet plant in wet soil, you'll simply trap that as well, causing rot in plant crowns, and in the case of dahlias, the tubers. 
    You can avoid that issue in wet areas by using a cloche instead, or even a hanging basket with fleece [or similar ] over it and pegged down :)
    It's a place where beautiful isn't enough of a word....

    I live in west central Scotland - not where that photo is...
  • FireFire Posts: 18,951
    edited October 2018
    I have various ones in large pots this year and was thinking of cutting the greenery back and fleecing the pot. Mine have been stunning this year, esp BofL and I def'ly want to try and hold on to these ones in perpetuity.

    With dahlias in the ground, doesn't it rather depend on the planting soil? If not very well drained they are liable to rot. Begonias also.

  • Nanny BeachNanny Beach Posts: 8,716
    Yes, Fire, you are correct, its usually a combo of wet/cold, that does things in, first frost today, 1.1d outside, (air, not ground) got the bubble wrap for no one greenhouse, couldnt do it this week, grandkids staying, so busy with them. Thanks fairy, so basically I need warm,dry soil, mulch, I did manage to keep a couple of tender fucshias a couple of years back, I wasnt well, so they didnt get dug up, (normally in pots anyway) Imulched with straw, and yes, put a metal hanging basket over the top, and they survived.I will try a few things, thanks folks, if they dont survive, at least I have tried (and failed LOL)
  • FairygirlFairygirl Posts: 54,794
    Yes - experiment a bit NB. Don't insulate wet,cold ground, just dry  ground, and remember that a degree or two of frost will rarely affect any plant, even half hardy ones, if it's combined with dry ground. :)

    A prolonged spell of frost is different, and even then, only when it's well below zero, the ground's been cold and wet, and it's with half hardy plants rather than fully hardy. 
    It's a place where beautiful isn't enough of a word....

    I live in west central Scotland - not where that photo is...
  • BraidmanBraidman Posts: 273
    Just have had a hard frost, all dahlia foilage has been blackened though I will wait until they get another blast and finish the foilage off completely!

    I dont lift the tubers right away, let them get any goodness from what ever foilage is left!

    I am able to save most varieties that I have season on season with the exception of Eveline and BofL, ( no what size  Evelines and BofL tubers are)!

    On some occasions I have washed all soil from them other time I leave the soil on, it does not seem to matter, washed or not!

    The biggest problem is finding space to store them!
  • Nanny BeachNanny Beach Posts: 8,716
    Wasnt a frost the other morning, it was condensation on the car, today there IS a frost, Braidman, I still have one empty greenhouse, (where I put pelargoniums,fuschias, there are a couple of bananas in there at the moment.  Dont know most of the varieties, only one, a really tall deep purple was labeled, and I have lost that!.  Fingers crossed then!
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