July 24

Gardening in a Changing World by Darryl Moore part 5

Plants as possibilities.

In the early 1900s a Swedish botanist, Gote Turesson, discovered what he called ‘ecotypes’ of plants which is the same plant but with small genetic changes depending on where they grew. Understanding the ecotypes of plants provides a better fit of plant to place with climate, soil, latitude and altitude giving the greatest range of ecotypes.

How can this prepare us for the future? Well, some ecotypes are better adapted to warmer temperatures and so may help in a changing climate. Different ecotypes offer different rates of carbon sequestration and oxygen provision. Variations in leaf size and shape offer alternative responses to light and moisture. They can extend flowering seasons and therefore will be suited to different pollinators. Now, instead of saying right plant, right place we can say ‘best plant in the right place’.

Since 2012 Sjoman working at Gothenburg Botanical Gardens has been looking at ecotypes in trees to ensure the best plant not just when it was planted but for long-term success. His focus on drought tolerance of trees means that it will be possible to diversify the trees planted in urban areas. And we know from earlier chapters that a greater diversity in plants + a greater diversity in wildlife plus a greater likelihood of surviving temperature changes.

James Hitchmough has been focusing on this when looking for plants for his new house in Dorset and his research with Sjoman and others suggests that adaptation of trees in urban areas needs to be studied in greater detail to match the tree with the specific site, e.g. near a pavement or a busy road. The limiting factor here is lack of knowledge.

Plant communities are not, as previously thought, in competition with each other. Many plants have positive interactions known as facilitations where one species alters the environment for another and enhances their growth, reproduction and survival. This might be through reducing temperature, moisture or nutrients. Trees do this by moderating the light levels underneath them as well as the moisture content and alters the nutrient levels through leaf drop. Some plants will provide shelter for others such as in windy environments and enable it to survive in conditions it wouldn’t normally. This can also be planned for in changing climates.

But what about what is going on underground? Roots do not just anchor a plant into the soil but also transports carbon into the soil and extracts nutrients and water for growth and reproduction. The microbial populations assist in adaptation to environment as do the plants themselves. Different leaves when they decompose offer different nutrients and this will affect individual plants within a community. This leads to the idea that if the microbiome of the soil is varied so will our microbiome be as well. We’ve moved a long way from colour theory here . Could we offer planting schemes that provide particular bacteria to people walking through them?

You can read part 1, part 2, part 3, part 4, part 5 and part 6 if you click on the links.