Towards the end of April this year (2017), the Royal Horticultural Society published an 87-page report entitled Gardening in a Changing Climate.
It is available to download, absolutely free, at https://www.rhs.org.uk/science/gardening-in-a-changing-world/climate-change: but, since the report has implications for every gardener and not every gardener will actually read it, I think that some of its findings deserve to be highlighted, thought about and implemented.
Let us start with an extract from the introduction by Professor Dame Julia Slingo OBE, Former Met Office Chief Scientist and member of the RHS Science Committee. “Climate change is likely to be one of the defining challenges of the 21st century and how we respond will determine our future prosperity, health and well-being and the sustainability of Earth’s natural environment.” She goes on to remind us that, in 2015, over 190 nations agreed to act to limit the increase in Earth’s surface temperature to less than 2ºC. Since then, President Trump has said that he will no longer commit the United States to the Paris Agreement. Still, that worrying news should not prevent gardeners the world over from doing our best to reduce our emissions and store more carbon and to contribute to a more comfortable and safer local environment. Every little helps. To quote Professor Slingo again, “We can start to plan now for the changes that we will need to introduce in our gardens.”
So what are some of the implications for gardeners? First of all, warmer springs and autumns will extend the growing season and some species will flower earlier and some will experience delayed leaf fall. Gardeners will need to do more weeding, mowing and pruning. And, while it may well be practical in the future to grow some species of plants which cannot withstand the present Scottish climate, gardeners will face a continual trade-off between a longer growing season and extreme weather events, one of which … increased rainfall … might well increase the rate that nutrients, particularly nitrogen, are washed out of the soil with implications for the amount of fertilisers we shall need to add to the soil and how often … and when … we shall need to add these fertilisers.
Then, as well as the probability of Scotland experiencing increased rainfall, it is also likely that we shall have more hot, dry spells which will be a boon to some existing pests and diseases and will probably lead to the arrival of unfamiliar ones which cannot thrive here at the moment. We shall need to think hard about the way in which we use water and the ways in which we can capture and store water during wet spells; we shall also need to understand more about biological and cultural controls in order to minimise the spread of pests and diseases, using chemicals only when there are no natural means of control.
One thing which won’t change is the desirability of gardening with Mother Nature, choosing plants which thrive in the prevailing environment. This will mean some changes to the plants we grow in our gardens. Since earlier flowering might disrupt host-pollinator associations, we should plant a diverse variety of pollinator friendly plants with different flowering times. We should be mindful that trees planted now might not be suited to the climate in 2050; and we should remember that trees and plants remove CO2 from the atmosphere and reduce the risk of flooding, making soft landscaping much more enviro-friendly than hard landscaping. And finally, the report recommends that we reduce the use of irreplaceable resources like peat; reuse household materials and seasonal items; recycle our garden waste; and help stimulate demand for recycled products by buying recycled items.