Gardeners should plant native “tredges” – foliage between the size of a tree and a hedge – to boost England’s tree cover, the Royal Horticultural Society has said.

Taking inspiration from ancient woodlands could boost wildlife across England’s 25m gardens, according to experts, and help increase native tree cover. The UK’s woodland cover is approximately 10% and the government aims to increase this to at least 16.5% of all land in England by 2050.

A garden demonstrating this approach will be unveiled at the Chelsea flower show in May. The Woodland Trust: Forgotten Forests Garden by Ashleigh Aylett will represent a damaged ancient woodland, transitioning from a dark, monoculture conifer forest to a regenerated, thriving ancient woodland.

Her design will include “indicator” plants that can be used to identify ancient woodlands such as wild service tree and red campion.

The Woodland Trust has found only 7% of the UK’s native woodland is in good condition, with drastic knock-on effects for the wildlife that make these trees their home.

Though her garden will be an ambitious demonstration of recreating an ancient woodland, there are lessons that can be taken from it for all those with a green space at home, such as planting small native trees and “tredges”.

Mark Gush, the RHS’s head of environmental horticulture, said: “Often found in ancient woodlands, a top choice for gardeners seeking a small tree is Crataegus laevigata. It is a great example of a ‘tredge’, which can be both a standalone tree or a hedge.

“It strikes the perfect balance between beauty and functionality. With attractive foliage, flowers and haws, it is also resilient to wet and dry climate extremes, tolerant of clay soils, and there is research evidence to show that this genus is effective at capturing pollutants from busy roads in summer. Its thorny protective canopy supports biodiversity and helps alleviate flooding risks from summer thunder-showers through effective water uptake.”

The Woodland Trust is trying to make tree-planting more accessible for those who have small spaces and are worried about giant trees dwarfing their gardens. Native trees do not need to be large. Planting a small native species could provide spring blossom and plentiful autumn berries, without taking up much space. Diverse trees also provide benefits to the garden because different species have different root architecture, which improves the health and structure of the soil.

Aylett’s garden will also demonstrate “forest planting”, showing layered canopies, ranging from ground covers to herbaceous perennials, shrubs and trees of various sizes, which has the benefit of maximising species diversity in limited spaces, and providing protective benefits against climate extremes (hot and cold) offered by this approach.

Transitional gardening, where multiple different habitats give way to each other and have diverse borders in between, is a good way to emulate ancient woodland habitat at home, Gush said.

He added: “Woodland edges support some of the highest levels of biodiversity because they represent an ‘ecotone’ – a transition zone between different environments. Ecotones between two habitats are often richer in species than either. This is a concept that can be applied incredibly successfully to domestic gardens where ecotones abound – lawns to borders, borders to shrubs and trees, pond edges and more. Think softer gradual transition as opposed to hard cutoff.”

The RHS is encouraging gardeners to choose trees grown under the UKISG (UK and Ireland sourced and grown) scheme, which ensures they are raised from seed and helps prevent new pests and diseases from entering the country, one of the most significant threats to native trees. For smaller gardens, instead of fences or walls, they ask that people consider planting a native hedge. This allows people to include native species without needing a huge garden, while also providing valuable food and habitat for the wildlife that relies on them.

After the show, the Woodland Trust garden will be relocated to Hawthorn primary school in Newcastle upon Tyne. The school is situated in an area with low tree cover, so will increase access to trees in a neighbourhood where canopy cover is limited.

‘Tredges’ that have environmental benefits in the UK, as chosen by the RHS

Beech (Fagus sylvatica)

Holly (Ilex aquifolium)

Western red cedar (Thuja plicata)

Common yew (Taxus baccata)

Hawthorn (Crataegus monogyna)