Hi, I need to clear my flower beds ready for spring planting. Do I have to wait for a frost to kill of the dahlia foliage or can I just cut them back and lift them?
You can do either tayberry. I find it's better to leave them in till after the foliage has been blackened by frost, the tubers are bigger if they are left that bit longer.
I'm with Dave. If you have the heart, if you cut all the flowers off, I believe all the energy associated with their production goes to swelling the tubers.
I've been lifting dahlias for a few years now and pretty much cut them down when I feel ready to clear and store. No real logic. Is it better to cut all flowers off and leave them for a while then? I've stopped deadheading now as I know it won't be long before I lift but I'm wondering if that's a bad idea as they'll start putting energy into forming seed heads...?
I have also contemplated leaving them in the ground for a year and seeing what happens....I would of course cover with a good mulch and some straw.
Rob, we used to live in Hants with very sandy soil and not much rain. I didn't lift my dahlias and only lost one after a nasty winter.
We now live in North Devon on heavy clay and I'd not dream of leaving them in the ground. I have to lift all 200 odd plants and store them in the garage over the winter.
I'd advise you to carry on dead-heading as you rightly point out they'll waste energy forming seeds.
I took all the flowers off last week and now I'm going to lift, dry and store them. I'll and see what flowers I get next year.
If they haven't been blackened by frost then leave them upside down for a bit before packing them for storing to let the sap run out.
Last year I just took a potted one into a unheated but slightly frost proofed greenhouse and let it dry out itself and picked up dead leaves etc as they dropped it came through fine again this year but it was a mild winter
I'm very tempted to do this Lizyann with my chrysanthemums and dahlias. But I haven't got a greenhouse so I'm going to put them in the garage. For the dahlias in the ground I'm just going to mulch them well and the begonia tubers ... I still haven't decided. I may take them up but they're still flowering well. I may just heap mulch on them too and see what happens. I guess it depends largely on what sort of winter we have ... and maybe I have to learn the hard way.
Hostafan - do you leave your hostas in the ground? I've got a note on my spreadsheet to mulch them well in February/March but otherwise just leave them alone but I can't remember where I got that info from now.
I have what looks like mildew quickly spreading all over my dahlias. They've flowered well this year, but they're clearly approaching the end of their cycle now. I don't think any of the buds will reach flowering.
Should I also leave my foliage until it dies of its own accord, or could the mildew poison the tubers?
I'd not worry too much about the mildew Tomsk