Lichens, slime moulds and wasps: RHS lists top beneficial wildlife for garden


Biodiversity crisis leads horticulturalists to highlight gardeners’ role in conserving wild flora and fauna

In not so distant times, a list of garden wildlife for many horticulturalists could have been a list of deadly enemies, containing aphids, slugs, snails and other creatures previously thought of as irritants. But as awareness of the biodiversity crisis grows, horticulturalists have become more aware of the importance of wild flora and fauna, and the important role gardeners can play in conserving it.

Now, the Royal Horticultural Society (RHS), the largest gardening charity in the UK, has released a list of the top beneficial wildlife to welcome into the back yard. Its list is made up of the most asked about species by its members, which have found them in their gardens and wanted to know what they are and if they are beneficial. Topping the list are lichens, which can often be found growing on trees or shrubs. The RHS hopes to raise awareness that lichens provide food for other garden wildlife and create new habitats by providing shelter for invertebrates and nesting materials for birds and mammals. They are also often associated with good air quality, as they carry out photosynthesis to capture atmospheric carbon. Certain lichens also absorb atmospheric nitrogen, a common pollutant. They regulate water and humidity levels by soaking up moisture during wet weather and slowly releasing it as water vapour afterwards.

Some additions to the list may be surprising to some, with wasps named as a beneficial creature to embrace in the garden. However, they are vital garden predators, feeding on everything from caterpillars to greenfly. Multiple fungi species also make the list, with people curious about the mushrooms growing in their garden. Sulfur tuft and inkcap mushrooms are often confused for the damaging honey fungus as they appear in groups in the autumn, but these beneficial species help recycle dead wood and support plant health.

The RHS recommends adding woody mulch or retaining pruning cuttings from healthy trees to encourage beneficial fungi in the garden.

Slime moulds should also be embraced, the charity said, as the organisms eat bacteria which decompose plant material, contributing to the nutrient cycling in a garden as they in turn are eaten by invertebrates such as nematodes. The rose chafer beetle (Cetonia aurata) is an eye-catching species on the list, this bright metallic green beetle often appears from May and the larvae feed on dead, decaying matter, helping composting in the garden. The organisation, which runs Chelsea flower show, used to put out a list of garden “pests”, but stopped doing so last year as the idea of eliminating wildlife is outdated when we are in a biodiversity crisis.

Instead, it has over the past year been trying to do “positive PR” for wildlife including slugs, snails, aphids, ants and ladybirds, which have tended to be destroyed in gardens in recent decades – often under the advice of garden experts. Its entomologists have been raising awareness of how a garden which has a balanced ecosystem can get rid of many issues which “pest” species cause.

The charity plans to be “biodiversity positive” by 2025, planning, among other goals, to increase wildlife across all their gardens. The RHS is encouraging gardeners more and more to focus on the benefits of having a biodiverse garden and the contribution each species makes to a healthy ecosystem and the ways increased biodiversity can prevent any one species becoming to prevalent and harming plants. Dr Liz Beal, an RHS plant pathologist, said: “We have seen a huge increase in gardeners wanting to find out more about the organisms they can encourage into their garden to naturally ward off the species that can be more damaging to their plants. Many of the gardeners that get in touch are also very curious about the wildlife they find and what they do, rather than looking for ways to get rid of them.

“A healthy garden ecosystem is home to a wide variety of wildlife, and we hope this list will help celebrate some of the friendly garden species that have a whole host of benefits for our plots and the wider environment.”

The top 10 beneficial garden species for 2022:

1.    Lichens

2.    Native ladybirds

3.    Pollinators

4.    Solitary bees (Aculeate hymenoptera)

5.    Sulphur tuft fungi (Hypholoma fasciculare)

6.    Slime moulds

7.    Rose chafer beetle (Cetonia aurata)

8.    Ink cap mushrooms

9.    Hoverflies

10. Social wasps


Helena Horton