From 'Death', Life

I know I go on about it, but I am always amazed at how plants will struggle to survive the seemingly impossible. I over-winter my outdoor pots in the garage behind a translucent glass-fibre door, and, to be honest, I thought these geraniums were a goner this year after being subjected to the winter frosts protected only by a sheet of newspaper.

Once plants lose some water and become a bit limp, their frost-resistance greatly increases. This is partly because the sap becomes more concentrated and freezes at a lower temperature, and partly because the cell contents shrink away from the cell walls, so even if the sap does freeze there will be room for expansion without rupturing the walls. Some plants do actually add chemicals to their cells to lower the freezing point.

I know the pots look untidy, but they seem to survive best like this. I never cut out the dead until the new growth starts, and then I cut back to the new shoots. I have tried cutting back earlier, but it doesn't seem to work, not for me, at least.