Time to wrap up your warm-climate plants
We all feel the onset of autumn: that first day you wish you had a scarf, or the evening you draw up a blanket around you on the sofa; or instinctively move to the sunny side of the street.
It’s not just you – all those far from home in your garden are wishing they had a scarf, too. Globe artichokes, potted lemons, cannas, dahlias, pelargoniums, bananas, fuchsias, tree ferns and Melianthus major hail from warmer climes, and at best just about tolerate our winters; at worst they give up the ghost and haunt our springs with dead stems. All of these can take a few cold nights, but it’s the flux between temperatures, and wet and cold, that makes them sulk and then give up. No one wants wet feet that then freeze – it’s the quickest way to send the cells to mush – but while frosts come in many varieties, the killers tend to be those where repeat freezing is followed by rapid thawing.
The larger plants (bananas, tree ferns and M. major) must be wrapped in situ. Dry bracken is excellent for packing around the stems; dry autumn leaves and straw work just as well. A chicken-wire cage will keep everything in place, as will fleece that’s been tied. An internet search for yuki-gakoi, which roughly translates as snow enclosure in Japanese, will teach you that there’s a fine art to winter wrapping, and that a little hat on top of whatever you want to protect is essential to keep rain and snow away from the crown of the plant.
Traditionally, tender perennials such as cannas, dahlias and gladioli are lifted before the first frosts of autumn and stored, to be replanted in spring. The tubers and corms are dug and left to dry out for a few weeks in a greenhouse or a garage, and then packed in crates or pots with dry compost, leaf mould or sand, where they are stored until spring. This is an excellent method, but does require cold but frost-free storage. You cannot store the tubers in your house: it will be too warm and wake them from dormancy, where, with inadequate light, they exhaust themselves trying to grow. If you don’t have storage, your other option is to insulate the ground they are in.
In sheltered gardens it’s possible to put a deep layer, several inches at least, of dry mulch (garden compost, leaf mould, straw or potting compost) that will insulate the soil from ground frosts. The trick is keeping this mulch dry, covering it with a cloche if necessary.
Potted pelargoniums, citrus and pomegranates will need very sheltered conditions; sometimes it’s possible to get them through winter in the lee of the house with layers of fleece and polystyrene under the pots, but really they want to come indoors, which may entail drastic pruning. Porches, sunrooms and other cool rooms are best. A spot next to a radiator will cause them to drop all their leaves, as they rapidly dry out, and sulk.
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