Gardening Time: How ‘tremendous crops’ might assist cut back air air pollution in properties and gardens


Experts are looking at the environmental multitaskers who can help you get some fresh air, writes Hannah Stephenson.

We all know about poor air quality in cities, which has to do with traffic, the lack of green spaces and gardens that give way to tough landscaping and driveways.

According to a recent survey of 2,056 adults commissioned by RHS, one in three people in the UK is affected by air pollution, while long-term exposure to air pollution can lead to chronic cardiovascular and respiratory diseases, according to Public Health England.

However, there are certain super plants that can help absorb pollution in transportation hubs, new RHS research has revealed.

“It’s easy to get environmental benefits like cooling, flood control and pollution control by growing plants in our gardens and homes,” says Dr. Tijana Blanusa, Senior Horticultural Scientist at RHS.

“Plants have the amazing ability to make all of these things invisible, but not all are created equal.

“Some plants are particularly good at supporting wildlife, for example, but many can have several benefits.”

This is where Blanusa and his RHS expert Leigh Hunt recommend “superplants”, environmental multitaskers that can help soak up some of this pollution in various situations in your garden and home.


Hedges are excellent at filtering air pollution and trapping them by their rough / hairy leaves and stems until they are washed to the ground by the rain or fall off with the leaves.

Cotoneaster franchise. Photo credit: Joanna Kossak / RHS / PA.

One of the top plants is Cotoneaster franchetii, which is at least 20 percent more effective against pollution than other shrubs.

It’s not your typical hedge plant, but when put in shape, it’s a top performer. Other options are Thuja plicata (western red cedar) and Taxus baccata (yew). Plant between the source of pollution and where you are – usually between the street and the house. Bigger is better, so aim for a height of at least 1.5 m and a width of at least 1 m.


Containers are useful for growing all types of plants on paved and balcony areas. If you rent, you can take them with you when you move.

Include plants to support wildlife, from pollinating insects to invertebrates. Plants with different structures (shrubs, perennials, climbing plants) offer different habitats, with flowers and berries providing food.

Even a common climber like ivy (hedera helix), which can be trained from a pot on a house wall to create a green surface, offers shelter, nectar and berries – and is native to the UK.

It is also crucial in helping with CO2 capture and dehumidification and, if raised by the side of a building, can help with internal temperature regulation.

Otherwise, try something from the list of RHS plants for pollinators that will fit in your containers.


Borders offer the most space. Bigger is better. If you have room for a tree (great air purifiers), plant one.

Our native hawthorn is a big little tree.

In addition to showy white flowers in late spring, there are fruits (haws) in autumn.

Not only is it a great plant for wildlife, but it can also help where flooding is a problem.

The leaves and stems in the canopy catch the rain and slow down the passage to the ground.

And this tree also splashes water from its leaves, helping to suck excess moisture out of the soil as it grows.

One shrub that can help is the cheerful yellow-flowered forsythia.

Green roof

These help cover hard roof surfaces that collect the sun’s heat during the day and release it at night, making our urban areas warmer and particularly uncomfortable during heat waves.

A sedum green roof. Photo credit: iStock / PA.

Traditionally, a green roof is a mat made of sedums that grow in 5 cm light growing media.

However, if you can use a deeper substrate, consider other plants, including lamb’s ears (Stachys byzantina), which actively cool the air by transferring moisture (a bit like sweating) and are much more effective than sedum.

There is no reason to restrict the lamb ears to the roof, however. You can still plant it in pots and borders for a localized cooling effect.

Another top cooling system is sage, which of course has the added benefit of being perfect for the kitchen too.


Bringing nature into the home has become all the rage.

In addition to being beautiful, houseplants also help improve air quality by drawing in air through the pores in the leaves and stems and removing contaminants.

These include compounds such as carbon monoxide and particulates (dusty particles) and volatile organic compounds (VOC) – a large group of substances that are released from furniture, cleaning products and paints that can have harmful effects on human health.

The first simple houseplants include the peace lily (Spathiphyllum wallisii) with its white, long-lasting flowers.

Just keep the compost moist and keep it out of direct sunlight so it can grow easily.