By Russell Jordan
If there’s anything that springs to mind about this past year, especially the last six months, it’s the copious amount of rain that we’ve had. Here in the west of the country we can expect to be wetter, and consequently milder, than the extreme east of the UK due to benefiting from the ameliorating influence of the ‘Gulf Stream’. There are fears that these warming currents, that lap our south western coastline, a function of the Atlantic Meridional Overturning Circulation (AMOC), are already at their weakest in sixteen hundred years and could fail completely as early as 2025 (or as late as 2095). As with so much that is happening to our climate these days, the shutting down of the ‘AMOC’ is due to the melting of the icecaps as global temperatures continue to rise with sea temperatures following suit.
We benefit from higher average annual temperatures as a consequent of the ‘AMOC’, with a consequently longer growing season and an increased number of frost-free days, which is why we can grow some borderline hardy plants in our Dorset gardens. The zenith of these ‘exotic’ gardens is exemplified by those wonderful gardens made in the especially sheltered coastal valleys on the south coast of Cornwall, the epicentre around Falmouth, where economic factors, sea trading Quaker families and an explosion in global plant hunting all came together in the ‘perfect storm’ of exotic garden creation.
Going back some thirty years, I remember visiting ‘Architectural Plants’, in Sussex not Cornwall, a nursery supplying garden plants grown predominantly for their foliage rather than flowers, and back then it seemed that global warming was a ‘good thing’ which was opening up a larger range of plants for our gardens. Having said that, I was there to film the various methods of protecting your ‘hardy’ exotics from the ravages of a British winter. This was at a point when everyone seemed to be acquiring hardy bananas (Musa basjoo) and tree ferns (Dicksonia antarctica) and I’m willing to bet that not many of those specimens are still alive thirty years later.
In the case of many doubtfully hardy plants, it is the winter wet that kills them, in combination with below freezing temperatures, and half the battle is to provide them with some kind of protection which also keeps them dry. In the case of hardy bananas the smaller ones had their foliage cut off and the ‘trunks’ cut down to a size whereby a chimney pot could be dropped over them. This was stuffed with dry straw and a lid, such as a weighted down roofing slate, to keep the rain out. With bananas as long as the growing point, at the base of the ‘trunk’, is kept alive, with adequate protection, then it will shoot again come warmer weather. Bananas also tend to produce new plants from basal offsets so that a single large specimen can become a small banana grove over the years as long as they are not killed off in a very severe winter (or if you forget to protect them!).
Tree ferns are much trickier to keep going because their growing point is at the top of the plant and it’s not as easy to keep this protected in the winter as it is with a banana. On top of this a tree fern is likely to be a large financial investment because they are most impressive when already at a decent height, over six foot, which means that they will almost certainly have been imported from Australia. They don’t like strong winds, exposed sites, too much sun or very dense shade and they like to be kept wet, not just at the root, during the summer months, especially when first establishing. Assuming that you’ve planted them in an already sheltered spot in your garden and have set up a drip irrigation system, to keep their growing point moist during dry weather, then winter cold is the next danger.
Protection can be provided by folding the large fronds over and around the growing point at the top of the trunk and securing in place with chicken wire or stuffing into a large old compost sack or dumpy bag. This will be unsightly so disguising the inner bag with a more aesthetically pleasing covering of hessian, or old potato sacking, will be necessary if the tree fern is in a prominent position. I’d be wary of covering the growing point with hessian alone because if this gets soaked wet through, a pretty likely event in our wet winters, then when temperatures drop below freezing this will become frozen through and the tree fern could still be damaged. The advantage of having an inner bag over your folded down fronds is that it should keep the inner layer dry and it is this that prevents severely low temperatures from penetrating right to the growing point. Extra wrapping of the ‘trunk’, actually the old bases of fronds from previous years’ growth, with copious quantities of horticultural fleece is also advisable.
That might all seem very specific and you may have ‘zoned out’ if you don’t have bananas or tree ferns in your own garden. However, December is often the first time that we are likely to face properly low temperatures, with overnight frosts, as winter take a proper grip and our gardens are finally denuded of all but evergreen foliage. The principles of protection and the importance of the microclimates that exist in every garden are worth considering, even if you are not gardening on the extremes. Just knowing that you have a spot in your garden which is sheltered from strong winds, has a southerly aspect or is just close to the house, is useful because that’s the place where plants are likely to come into growth a little earlier than elsewhere and die down the latest. It’s these favoured spots where you might want to plant a special plant, or just place a container full of spring bulbs, so that you get blooms a little earlier, maybe to bring into the house, than you would otherwise.
It’s these little things that are worth considering when evaluating your garden, whether you’ve had it for fifty years or if this is your first chance to make a garden. The winter months are a good time to make these assessments as ‘real’ gardening tasks are best kept for the balmiest winter days and thinking time, in the warmth of indoors, is a luxury worth indulging in. The garden is, helpfully, stripped to its bare bones at this time of year so you can get a clear idea of how the structure is working, especially when it comes to hedges, garden buildings, paths and lawns, and whether you need to make any changes in the year ahead.
From a practical point of view, now we are well into the ‘dormant’ season, it’s that time, yet again, when I bang on about obtaining plants ‘bare-rooted’! It’s the cheapest and most convenient way to obtain many of the trees and shrubs which will become the backbone of your garden, field or arboretum in the future. Roses are the plant which is typically bought while in its bare-root, dormant, state and there is a bewildering choice of cultivars available from a myriad of internet, formerly known as ‘mail-order’, specialist nurseries.
If you are stuck for a Christmas present, for a gardening friend, then getting them sent a beautiful rose plant, or some other choice shrub, might be a solution. If you are feeling especially generous then teaming it with a sturdy fork and spade set, a pair of secateurs (I still favour ‘Felco’s) and some ‘Rootgrow’ will really set them up and make it a memorable Festive Season that keeps on growing, year on year.