Images: Howard Rice
Climate change poses gardeners significant challenges as we care and plan ahead for our outdoor spaces, as Sally Petitt explains
How many of us gardeners consider where our plants originate from? That doesn’t just mean knowing which garden centre we bought them from, it means understanding where in the world they naturally occur, and what the local conditions are. This knowledge can help us understand which plants best suit our own gardens and follow the old gardening adage of ‘right plant, right place’.
Recent evidence suggests plants began colonising the land more than 500 million years ago, and have evolved since that time to produce the plants we know today. Plant evolution is slow and is influenced by genetic composition, as well as climatic factors. Light, temperature, water and humidity are hugely influential in plant development, affecting plant growth and geographic distribution.
If any of these factors change, even slightly, it can have a detrimental impact on plant health and even survival, with changes to environmental factors affecting entire populations or species. For example, desert plants have evolved to survive with limited amounts of water, but if climate change brings increased rainfall to these areas, the desert plants we are familiar with may cease to exist.
There are also concerns that the pace at which climate change is occurring, as well as the subsequent environmental change, means plants may not evolve at the same rate and will become either threatened or extinct. High-altitude alpine plants, for example, are considered to be at high risk in a warming climate. They have evolved to survive in extremes of temperature and light. As temperatures increase, the only option they have is to migrate upwards to escape the heat, but there is limited scope for them to do this.
For many known plant species, changes to environmental conditions such as reduced water can cause stress to the plant or even death. Unfortunately, the resulting stress could also increase a plant’s susceptibility to attack from pests and disease.
Planning ahead
Not only does climate change affect plants in their natural habitats, but it also has an impact on our garden plants. At Cambridge University Botanic Garden, we have taken daily weather readings since 1904. In 2019, we experienced a temperature of 38.7°C, which was the highest temperature ever recorded in the UK (a record that has since been exceeded), and on 26 May 2026 we recorded a maximum temperature of 34°C, which coincided with a dry spring and also followed a wet winter. Historically, such weather patterns would not have been considered normal.
In order for our living collections and plants to survive in the future, we are making adjustments to our horticultural practices. In our Dry Garden, plants such as Hibiscus ‘White Chiffon’ thrive alongside Stachys byzantina (lamb’s ear) and Euphorbia myrsinites (myrtle spurge), and in the Dry Meadow steppe and prairie plants like Oenothera macrocarpa (evening primrose) and Dianthus carthusianorum (Carthusian pink), flourish in the dry, well-drained conditions.
These garden features, along with new and future plantings, have species suited to our changing weather patterns and that demonstrate climate resilience. Cambridge University Botanic Garden expeditions to countries such as Croatia, Chile and Kyrgyzstan enable us to introduce plants from habitats that are predicted to align with Cambridge’s future climate and give us scope to adapt our collections.
We are also developing plans to improve our irrigation system, not to increase our water consumption, but to use water more efficiently in the future. Proposals include a new ring main and pumps to more effectively distribute water across the site, monitor soil moisture levels and also increase our rainwater harvesting capacity. Such measures will allow us to protect the garden and its collections for future generations of scientists, horticulturists and visitors.
Adapting at home
Similar steps can be made in your own garden. Choosing plants that suit the weather will make gardening easier – think about ‘right plant, right place’. Understanding where a plant originates from and what conditions it grows in will naturally inform whether it thrives in your garden in the future.
Collect rainwater in a water butt to limit your use of mains water. If you need to use a hose pipe, repair leaks and aim to water early in the morning for the most benefit. Only water plants with signs of stress – many established plants (including lawns) will go longer without water than newly planted specimens.
Gardening in a changing climate can be challenging and we need to adapt our gardens to match the future weather conditions. With careful selection we can add new plants to our gardens that will be more resilient to changes in the weather.
While this may mean that traditional herbaceous borders become a thing of the past for many of us, there is still plenty of scope to create beautiful gardens that will thrive in the future.
Sally Petitt is head of horticulture at Cambridge University Botanic Garden