Planting and Global Warming

Daphne Ledward

The easiest way of getting yourself a spot in the on the gardening pages of the weekend Broadsheets is to send them a piece on gardening and global warming. Grey leaved, Mediterranean plants are a Ďmustí, and we will all be growing pineapples and ginger on our allotments in a couple of years.

But the truth and practicalities are, in fact, very different from what the uninformed gardening media will tell you.

Take Mediterranean-type plants, for instance.

Yes, these will thrive with minimum feeding and watering in a hot, dry summer. But what happens during a normal British winter?

The rain comes down, the roots get soggy, the hairs on the leaves become waterlogged, and the plants seldom survive their first winter.

We are told to mulch with anything we can get our hands on, but I know from experience that if you mulch Mediterranean-type plants, the soil retains too much water and they rot.

By all means, grow this kind of plant in a restricted environment, like a raised bed or tub, where you have control over the weather (watering sparingly when necessary in summer, moving under cold glass in winter Ė if you can afford it). But it will be a long time before we need to forget about all the garden plants we know and love.

This year (2009) has been a typical example. In Lincolnshire, we had a dry, warm spring and early summer, followed by a wet July and first half of August. We then had weeks and weeks of dry weather, broken only by one downpour, until the second half of October, when the heavens opened and now the soil moisture is back to normal. But this is a different pattern from last year, and the year before, and the year before that, so we cannot as yet make any generalisations as to what we should expect in years to come.

Admittedly, autumn is late. As I write this (1st November), the colour in the garden is magnificent. I still have magnificent hanging baskets of begonias and impatiens which blend so well with the autumn colour on the trees and shrubs. The roses are still in flower, and the hostas are only slowly turning yellow. I am champing at the bit to get on with my spring bedding and annual tidy up, but the herbaceous plants and shrubs are much too good to start cutting back and I have decided to lie back and enjoy the display while it lasts.

Therefore, I donít dispute that the weather is different from what it was when I was a child. We seldom get the penetratingly low temperatures of January 1963, and, if we do, they donít last for weeks. We donít get the snows of early 1979, which were still hanging around in some parts in early May. But we still get sufficient of the kind of weather that our popular garden plants enjoy. It is too early to discard them in favour of cacti and bromeliads.

So, rather than ripping out traditional borders and abandoning our favourite trees and shrubs, what easy steps can we take to adapt to the weather shift we are experiencing at present?

  • Go back to planting in the dormant period, rather than sticking stuff in when you want to see it, during the summer. Then you wonít have to worry about serious watering to prevent the compost round the roots drying out until theyíve had a chance to get out into the soil.
  • Plan your growing round saving adequate rainwater.

  • I donít mean the piddling little water butts like oversized buckets you can buy in hardware shops and by mail order for exorbitant amounts of dosh, which overflow during the first short shower and are empty by the end of the second day of a dry spell.

    There are many farmers and other businesses that buy liquids in cubic metre tanks. These are not usually refillable and would normally go to landfill or for recycling. Many firms sell these off for a few pounds Ė you can even buy them new from the manufacturers for less than you would pay for the same water capacity in domestic butts if you know where to look.

    A cubic metre of rainwater goes a long way and takes up little room if you plan your garden properly. I recently installed one such tank in the garden of a new property where planning permission had been refused many times because the plot was too small. The miniscule garden was designed to take account of the rainwater available; the tank itself is hardly noticeable.

    And why, I wonder, do more planning authorities not get their act together and insist on underground rainwater tanks before allowing new properties to be built?

  • Admittedly, a few plants are starting to labour under the climatic conditions they are experiencing at present. One example is the Japanese maple, which needs cool, moist, partially shaded, acid conditions to thrive. These are very exacting requirements, so Acer japonicum is easily upset, and the Japanese maple is not a native of the British Isles anyway.
    1. It is very sad that the maples of Westonbirt Arboretum are showing signs of stress Ė they are in my own arboretum - but maybe we should be thinking less in future about growing plants in alien environments, and concentrating on species that can cope with the wide range of weather conditions they are likely to experience in this climate.

      The deciduous spindle, Euonymus elatus, is one such shrub. Its autumn colour rivals any Japanese maple, thrives (so far) in our conditions, and has pretty and fascinating fruits as well.

      I certainly will not replant any Japanese maples- or anything similar that is showing signs of being unhappy - that I unwisely planted in a rash moment.

    In the meantime, rather than altering the habits of many generations, why not appreciate the additional benefits that the present climate shift to warmer temperatures is giving us, and add such architectural gems as cordyline and phormium to our shopping list of hardy plants? Thirty years ago I struggled with such species, now I rely on them and others like them for year-round garden impact.

    And if we donít have to dig up bedding pelargoniums every year, well I, for one, will be very thankful.

    Daphne Ledward

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