A cold and frosty morning

The other morning we had the first proper frost of the winter, which froze the water in the bird-bath and blackened the dahlia foliage.  At last.  The dahlias stopped flowering a few weeks ago, but you’re supposed to wait until the foliage dies back before lifting them for winter storage, and they had been stubbornly staying green(-ish) despite a couple of light frosts and a thin covering of snow last weekend (it melted after a few hours in the sun).  I’m now digging them up gradually, though the ones I really want to get lifted are those in pots; I need the pots for the spring tulips! 

I’m wondering whether I should put more of the dahlias in the ground next year rather than having them take up space in the pots.  If we really are going to get milder winters, they will die back later and later, and the tulips won’t have a chance.  On the other hand, they’re invaluable for filling the space in the two really big pots, which need something of substance to make an impact; a smattering of bedding plants just wouldn’t do the job.  Maybe next year I’ll put some in the big pots and plant all the others in the borders, or in one of the veg beds for cutting; the ones in the medium-sized pots didn't flower well this year in any case.

(I also wonder what would happen if I lifted them before they turned black?  Maybe I should do an experiment next year and see; I have plenty of tubers, especially of ‘Bishop of Auckland’, so I could spare a couple, and if they didn’t survive I would have enough of the others.)

Blackened dahlia foliage isn’t very photogenic, so instead here is a picture of my beloved ‘Bishops’ Children’ in full flower (they are now drying off in the greenhouse).  I still have some of the seed, and may sow a few more in the spring; I usually lose a couple of tubers in storage and it would keep the numbers up.

'Bishop's Children' dahlias in their heyday

I’m toying with the idea of moving the pot of gazanias into the greenhouse to overwinter.  They didn’t all flower, but they’ve made strong plants and they have lovely bright sunny yellow flowers.  On the other hand, I still have seed of those too, so I could just grow more in the spring.

Usually I try to overwinter all my half-hardies in the greenhouse, but they take up a lot of space, and as some of the plants are no longer in their first flush of youth I’m not sure it’s worthwhile.   This summer and autumn I took cuttings of the osteospermums and all the penstemons – I read somewhere that penstemons lose vigour after a couple of years and are best replaced – and may well discard most of the parent plants.  The little baby plants will be much easier to overwinter; certainly they will take up less room.  The penstemons might be a good replacement for the dahlias in some of the medium-sized pots in the spring; they could be more easily taken out when it’s time for the tulip planting.  Just a thought.