With the first properly cold weather now on the horizon, a small gardener’s conundrum is what to save from the frost and what to leave to a chilly fate. Those lucky people with a conservatory, small greenhouse or generous windowsills are in the best position to overwinter tender plants. Sadly we have none of these, so it’s time for some tough decisions!
Plants that grow from bulbs and rhizomes and which die down in winter are less of a challenge. They generally dislike being wet during the winter, so we tuck them away in the dark, unheated shelter of our undercrofts as soon as the foliage has yellowed and died. It’s important to wait for this to happen so that the energy generated by the leaves can be stored up in the bulbs and rhizomes for next year. We leave them in their pots, tipping them out and replacing with fresh compost in the spring. If you don’t have a cellar, the shelter of an evergreen hedge or the rain-shadow at the foot of a wall should do. Just check at regular intervals for waterlogging. If the plants are tender (such as Hedychium, Canna and Cautleya), remember that they are more exposed to frost if they are in a pot, so wrap the container with bubble wrap or hessian to protect it from the worst.
But it’s the plants that stay green throughout the winter that pose the biggest challenge. Last year we overwintered a 2 year old Mandevilla sanderi (above) in our London flat. Although it was very unhappy and lost a lot of leaves, once it got back into the garden it went off like a rocket. I returned home this week to find flailing stems of glossy foliage a metre long projecting from its neatly trained frame, as well as lots of lipstick pink flower buds. However, this year it’s too large to fit in the car and there’s nowhere for it indoors, so what to do? It seems such a waste to let it go, but all-in-all it’s probably cheaper and easier to start again next year. Abutilon ‘Nabob’ in our London garden should secure a place on the right side of the French windows, where hopefully it will continue to produce its blood red flowers until Christmas.
Fuchsias, Coleus and begonias (unless they are very choice ones) fall into the same category and will be replaced by vigorous new plants next year. Osteospermums, in my experience, are never as good in their second year as they are if you start with new ones. All can be grown from cuttings, but again these need a bright windowsill to get them through the darker days. Below, Fuchsia ‘Orange Crush’ – still going strong this weekend.
One plant that I would never leave to the mercy of the elements is my 7 year old Aeonium ‘Schwarzkopf’. The slightest frost could reduce it to mush, so it comes indoors in October to enjoy the balmy climes of the bathroom. Joining it this year will be Aeonium ‘Sunburst’ and ‘Torchbearer’ which are too young to die. Another succulent, Aloe striatula, needs no such coddling, and will take everything the winter has to throw at it, including snow. It’s not the prettiest succulent, but it gets my admiration for its hardiness.
As for the rest, it’s a case of how much space we can find in the house and how quickly we can get them in. This year I’ve raised a number of Tecoma ‘Mayan Gold’ (below, image from davesgarden.com) and Plumbago capensis ‘Escapade Blue’ from seed and they will have to be squeezed in despite their increasing size. I’ll stop feeding these now so that they don’t grow tall and lanky through the winter months.
Luckily our mild climate means frosts are reasonably rare, so anything of borderline hardiness is still worth the outdoor challenge. Echium, Agapanthus, Melianthus, Beschorneria, Astelia and Isoplexis are all reliably hardy for us. Meanwhile, one large pink Mandevilla seeks a new home – must have central heating, large windows and room to grow!