I've always cut back Dahlias after the first frost. Looking at the long range forecast, there is no frost predicted for Oct or Nov. I was therefore wondering, when to cut back if there is not a frost?
I was always under the impression, from various sources, that frost was somewhat essential, as the dying back results in sugars returning to the tuber. Ive a lot of Dahlias, so it's quite a big job, hence my question. If the frost has no real benefit, same applies to canna plants, I was going to cut back all at the end of Oct regardless. In an ever warming world I suspect such questions will become more common! Thanks for the replies.
Mine are still flowering (although the ones newly planted this year haven't flowered at all). I won't be cutting them back as I tend not to cut anything back in autumn, leaving dying and decaying things to sink into the ground and provide habitat for critters and cutting back in spring. I leave my dahlias in the ground as my sandy soil means they don't rot and I get bigger and better plants the next year. But I'll lift the ones in pots in a few weeks.
I'd cut back as soon as you start to see the flowers and foliage fading naturally if there has been no frost - they'll start to look a bit tired as the days shorten or as they get battered by wind and rain. The tubers will continue to store food if the leaves are still functioning and have not been removed or blackened by frost so I'd leave them as long as you can. Or, for aesthetic purposes or your time availability, leave them as long as you want to, but no later than after the first frost.
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When you don't even know who's in the team
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