To celebrate the benefits of healthy plants, the United Nations designated 2020 as the International Year of Plant Health. By protecting plant health, we protect the benefits that plants provide to our health and well-being, to wildlife, the environment, our culture and our economy.
There are many ways gardeners can help keep plants healthy on their own patch and in the wider environment – here are some examples.
- Think of your garden as a mini ecosystem. Britain is home to more than 20,000 species of insects and few of them are garden pests – we rely on many of these insects for pollination, pest control, soil health and nutrient recycling. Even insect pests themselves are important, being part of the food chain for other wildlife.
- The use of chemical pesticides can kill beneficial insects like pollinators and lead to a later resurgence of pest populations. Use chemical-free pest control, such as physical barriers, sticky traps, pheromone traps, physical removal and biocontrol.
- Biocontrol nematodes are available to control slugs, vine weevil and fungus gnats. In our glasshouses at The National Botanic Garden of Wales, we use products like these in an integrated pest management programme.
A wildlife friendly garden is often more ecologically balanced, suffering less pest and disease issues.
- Encourage natural populations of predators and parasites by providing habitats and not using chemicals. Aphids are eaten by ladybirds, hoverfly larvae, lacewings and wasps. Slugs are eaten by birds, hedgehogs and frogs. Many small species of wasp parasitise other insects.
- Companion planting—growing flowers next to vegetables—can be used to attract beneficial insects.
- Crowded plants can harbour more pests and diseases. Maintain good airflow by giving susceptible plants enough space and pruning when overcrowded.
Stressed plants are more prone to pests and diseases, so choose the right plant for the right place.
- Growing blocks of the same plant (monocultues) can provide pest and diseases with an endless buffet of their favourite food or host. To avoid this, mix plants up a bit – for example, when planting a hedge, opt for mixed species.
- Know your enemy: identify any plant health problems carefully to work out appropriate actions – it may turn out not be a problem at all.
- Practice good garden hygiene by cleaning your garden tools, machinery, pots and trays.
- Covering water butts can prevent a build-up of fungal spores.
- If plant waste is dumped over the garden fence, garden plants may invade our natural habitats in Wales – dispose of garden waste sensibly by composting or using garden waste bags.
Look after your soil
- Soil health is key to plant health. Soil allows plants to take up water and nutrients and it contains mycorrhizal fungi which help plants to grow.
- Amend your soil to make it suited to the plants you want to grow, for example, by adding drainage or organic matter.
- Crop rotation can help to keep soil-borne pests and diseases in-check.
Sourcing new plants
- Be especially cautious when ordering plants and plant products online – they can come from afar and bypass plant health checks.
Imported plants can harbour new hitchhiker pests and diseases from abroad – to minimise this chance, source new plant material carefully, buying locally and UK-grown. This will help to keep out new devastating pests and diseases like Xylella bacteria.
- Monitor the health of new plants in your garden. Wherever possible, keep them away from other plants for a few weeks.
- Where possible, raise your own plants from seeds or cuttings.
- When on holiday abroad, appreciate plants where they are. Don’t bring plants or seeds back as you may bring home a new pest, disease or invasive species.
- If your garden suffers from particular pests or diseases, look out for plant varieties that are naturally resistant.