Plants to help filter pollution in gardens
Some plants can trap air pollution and so help to provide a barrier between a garden and busy road. These plants can be used to create a full and attractive border to help reduce air pollution in your space
Quick facts
- Plants with hairy leaves are often useful in trapping particles of pollution
- Dense foliage will improve the ability of plants to stop pollution
- Multiple rows of foliage offer a greater chance of catching pollution particles
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The planting plan
This pollution filtering planting design provides a range of plants that, once established, will thrive in most soils while providing a variety of interest throughout the year.
Choosing plants to filter pollution
A combination of dense evergreen foliage and, in some cases, fine hairs on the leaves, can help to act as a buffer and filtration system for the garden.
For maximum filtering effect, the yew hedge creating the back row of this scheme should be allowed to reach a minimum of 2.5m in height and at least 1m in width.
The conifers and Cotoneaster have small leaves that are good for trapping particulate pollution such as smoke. Cotoneaster also makes good groundcover. Keeping the ground covered with plants helps to prevent unwanted seeds from growing, and protects the soil surface from erosion and moisture loss.
Until the plants have filled out, an organic mulch, preferably homemade compost, can help to lock in soil moisture and suppress weeds. Mulches should be spread when the soil is already moist to help trap some of that moisture before it dries out in summer.
2 - Chamaecyparis obtusa ‘Nana Gracilis’ is a compact and slow-growing pine, with blue-green needles.
3 - Cotoneaster franchetii is an evergreen shrub with wide arching branches. Clusters of small white flowers in early summer, are followed by red berries.
4 - Thuja occidentalis ‘Smaragd’ is a conical conifer that can provide an interesting focal point in a border with bright green foliage.
5 - Pinus strobus ‘Secrest’ is a dense broadly conical dwarf conifer, with long blue green needles.
6 - Pinus densiflora ‘Low Glow’ is a slow-growing dwarf conifer that forms a compact mound. It has bright green to yellow-green needles, with small cones.
7 -Verbascum 'Pink Domino' is similar to ‘Gainsborough’ on the left, with dark green wrinkled leaves, and spikes of rose-pink flowers with a dark central eye.
8 - Elaeagnus x submacrophylla ‘Compacta’ is a fast-growing evergreen shrub. The green leaves have a silvery sheen, and it bears highly scented white flowers in autumn.
9 - Erysimum ‘Bowles's Mauve’ is an evergreen perennial with dark grey-green leaves and a profusion of bright mauve flowers over spring and summer.
10 - Elaeagnus pungens ‘Frederici’ is an evergreen shrub whose leaves are yellow centred with a dark green margin. Small fragrant flowers open in autumn.
11 - Stachys byzantina ‘Silver Carpet’ is a low-growing perennial with a dense carpeting habit, with silver-white furry leaves
12 - Verbascum ‘Gainsborough’ is a short-lived perennial with tall spikes of primrose yellow flowers from a basal rosette of grey-green leaves.
About pollution-trapping plants
Some plants can trap certain air polution particles and may also assist in other ecosystem services such as flood mitigation.Clipping the plants annually will result in denser foliage, which will help trap more particulate matter.
A simple planting plan helps create depth, interest and good coverage in a border.
The challenge with trapping air pollution
In RHS scientific studies, Cotoneaster franchetii has been shown to trap up to 20% more particulate emissions than many other shrubs or hedges, so it could be ideal along busy roads.
Having multiple rows of planting, if space allows, would also be a benefit.
Why choose a sustainable planting combination?
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The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.