Honey Fungus
Disease · Commonly affects: Roses, Rhododendrons, Privet, Apple trees, Plum trees, Birches, Conifers, Potentilla
Honey fungus is a destructive soil-borne disease caused by Armillaria fungi. It attacks the roots and lower stems of many woody trees and shrubs, often after drought, damage or other stress. It matters because an apparently established garden plant can decline quickly, and the fungus may spread from infected stumps through surrounding soil.
How to identify it
Look for poor growth, smaller leaves, premature autumn colouring and dieback, sometimes affecting one side of a shrub or tree first. Beneath loose bark around the base, honey fungus forms creamy-white sheets with a strong mushroom smell. Black, bootlace-like strands called rhizomorphs may be found in the soil or on roots. Clusters of honey-coloured toadstools, usually 30-100 mm across, can appear near the base in autumn, but are not present every year.
Damage
The fungus kills fine roots, then larger roots and the lower stem, cutting off water and nutrients. Leaves wilt or become sparse, branches die back and whole shrubs or trees may eventually collapse. It can travel from a dead stump to nearby susceptible plants, leaving gaps in borders, hedges and orchards that are difficult to replant successfully.
Prevention
Remove old stumps and as much major root material as practical before planting a new woody border. Keep trees and shrubs well watered during dry spells, avoid damaging roots and do not bury the stem base beneath heavy mulch or soil. Where honey fungus is known, choose plants regarded as more resistant and improve drainage. Do not move soil, logs or roots from affected areas to clean parts of the garden, and keep new planting well spaced.
How to manage it
There is no chemical cure for honey fungus. Dig out dead or clearly infected shrubs, including their principal roots, and remove infected stumps where feasible. Bag and dispose of the material rather than composting it at home. Check neighbouring plants for decline and reduce stress with watering and sensible pruning. Replant only after removing as much infected woody material as possible, using a resistant species or growing replacement plants in containers or raised beds with clean compost.
Honey Fungus: frequently asked questions
How do I identify honey fungus?
Look for poor growth, smaller leaves, premature autumn colouring and dieback, sometimes affecting one side of a shrub or tree first.
How do I prevent honey fungus?
Remove old stumps and as much major root material as practical before planting a new woody border.
How do I get rid of honey fungus?
There is no chemical cure for honey fungus.
General guidance for UK home gardens and allotments, focused on prevention and non-chemical control. For a confirmed diagnosis, the RHS or a local garden centre can help. Page updated 19 Sep 2026.