Tuck dahlias up for their winter hibernation as soon as the stems are blackened by frost
I arrived at the Chicken Garden this morning to find the big, handsome dahlias hanging their heads, their lush leaves turned slatey black and drooping disconsolately.
Abbie – garden owner – grows dahlias by the armful to cut for guests at the B&B, and very gorgeous they’ve been for the last few months. So there are two whole rows of them in the cutting garden as well as a dozen or so in various spots around the main flower beds.
If you’re leaving them in the ground, cut stems right back (if lifting, leave 15cm of stalk intact)
You can leave dahlias as they are till the blackened-leaf stage (and they’ll keep flowering, too, if you dead-head) but once the first frost has struck it’s time to leap into action.
Mulch thickly – at least 15cm deep. Autumn leaves are ideal for this as they don’t hold on to moisture as much as compost.
I always prefer to leave a plant in the ground if at all possible, and in the balmy south-west we’re in just the sort of place where you can get away with it with dahlias most years. But you never know quite what the weather has in store: if it’s a really wet one, or possibly even a really snowy one, you could still end up losing the lot.
I decided to cut my losses: so I’ve left the bigger (and therefore, I reason, more hardy) border varieties in the ground and lifted any smaller plants and also those in pots and containers where the roots are more exposed.
And finally: cover the whole thing with a layer of hessian (as here), insect-proof mesh, weed-suppressing fabric, old t-shirts… in fact anything that’s breathable. Two purposes: 1) it holds the leaves in place and stops them blowing off, and 2) it gives one extra layer of frost protection to the tubers. Pin down securely with bits of sturdy wire. And that’s it till spring (I hope…)
In the cutting garden, I have covered one whole row and lifted the other. They’re currently trimmed back to about 15cm and turned upside down to dry and drain, the shortened stalks poked through the slats of the greenhouse staging to hold them in place.
Next week, once they’re fully dry, I’ll pack them into boxes of damp-ish sand or spent compost and move them to the shed (drier than the greenhouse). After that I shall be going round with fingers permanently crossed till the spring warms up next year and I can pull back the covers to see if my luck has held. Here’s hoping…
