Blog: It’s a shock to your system and to your plants…
Our first frost of the season happened on November 28, down to -3 °C, and it had a dramatic effect on some of the more histrionic divas in the garden.
If you’re new to gardening and have plants that are borderline hardy, you’d be excused for thinking they are all going to die on you. Well, some might, but you have to take the rough with the smooth, as the majority will recover. Leaves will often flop and freeze, but as the temperature gradually rises, they will usually perk up. I took the frozen pictures for this post at 9.15am. By 1.30pm, the temperature had risen to a balmy 3 °C and all but the annual nasturtiums had recovered – this will spell the end for them.
First frost of the season – Dying back early
Some herbaceous plants, such as the very large-leaved ornamental rhubarb (Rheum palmatum) and Rodgersia, die back very early, leaving just their lumpy crowns on show. Remove any dead leaves as they rot.
Most herbaceous perennials will die back to soil level and lie dormant over winter, sprouting again in spring. Try to keep the dead growth on the plants, as it will protect the crowns, provide winter structure and act as overwintering homes for beneficial insects.
Borderline hardy plants will behave differently depending on where you live or how you grow them. Big-leaved lovelies, the honey bush (Melianthus, hardy to -5 °C) and Chinese rice paper plant (Tetrapanax rex, hardy to -10 °C), can be evergreen, deciduous, or die back to the ground depending on the winter temperatures they have to endure.
A helping hand to survive
The honey bush is in its first season in my garden, so I’ve packed bracken and netting loosely around its crown to give it a helping hand. The Tetrapanax has a thick mulch of old compost.
Your first frost of the season is a great learning experience. You’ll find out where the coldest parts of your garden are and any frost pockets, so avoid putting anything at risk there. Wet gardens suffer far more than dry ones in winter. Plants like lavender can’t bear the combination of cold and wet.
It fascinates me how the same plants can react in different sites. Echium pininana is a prime example. There’s a large two-year-old who self-seeded into pure gravel – that got through last winter without a problem and breezed through last night (Echiums are generally hardy to -5C but some of mine have survived a couple of nights at -7 °C with fleece).
First frost of the season – Location, location, location
Another self-seeder in the long border, a one-year-old, took umbrage, flopping horribly, although it did recover. It’s in soil which will freeze and in a far more open environment, so it is much more at risk. Luckily, Echiums self-seed voraciously, so any that survive the winter are likely to pass on their hardier genes to the next generation.
I think the biggest shock I got this year was the overnight transformation of Brunnera Looking Glass, whose metallic silver leaves turned to a mucky green! They did get their lustre back, but will die back until the spring. Finally, the key thing to remember is to dig nothing up that looks dead now. You may find it will sprout again as the temperatures warm up.
